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Yoo S, Kim DS, Hong WK, Yoo JI, Huang F, Ko HC, Park JH, Yoon J. Enhanced Ultraviolet Photoresponse Characteristics of Indium Gallium Zinc Oxide Photo-Thin-Film Transistors Enabled by Surface Functionalization of Biomaterials for Real-Time Ultraviolet Monitoring. ACS Appl Mater Interfaces 2021; 13:47784-47792. [PMID: 34585581 DOI: 10.1021/acsami.1c15565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Indium gallium zinc oxide (IGZO) is one of the most promising materials for diverse optoelectronic applications based on thin-film transistors (TFTs) including ultraviolet (UV) photodetectors. In particular, the monitoring of UV-A (320-400 nm) exposure is very useful for healthcare applications because it can be used to prevent various human skin and eye-related diseases. However, the relatively weak optical absorption in the UV-A range and the persistent photoconductivity (PPC) arising from the oxygen vacancy-related states of IGZO thin films limit efficient UV monitoring. In this paper, we report the enhancement of the UV photoresponse characteristics of IGZO photo-TFTs by the surface functionalization of biomolecules on an IGZO channel. The biomaterial/IGZO interface plays a crucial role in enhancing UV-A absorption and suppressing PPC under negative gate bias, resulting in not only increased photoresponsivity and specific detectivity but also a fast and repeatable UV photoresponse. In addition, turning off the device without external bias completely eliminates PPC due to the internal electric field induced by the surface functionalization of biomaterials. Such a volatile feature of PPC enables the fast and repeatable UV photoresponse. These results suggest the potential of IGZO photo-TFTs combined with biomaterials for real-time UV monitoring.
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Affiliation(s)
- Seonggwang Yoo
- School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Republic of Korea
| | - Da Som Kim
- Division of Biotechnology, College of Environmental and Bioresources Sciences, Jeonbuk National University, Iksan, Jeollabuk-do 54596, Republic of Korea
| | - Woong-Ki Hong
- Center for Scientific Instrumentation, Korea Basic Science Institute, Daejeon 34133, Republic of Korea
| | - Jung Il Yoo
- School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Republic of Korea
| | - Fu Huang
- Division of Biotechnology, College of Environmental and Bioresources Sciences, Jeonbuk National University, Iksan, Jeollabuk-do 54596, Republic of Korea
| | - Heung Cho Ko
- School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Republic of Korea
| | - Jung Hee Park
- Division of Biotechnology, College of Environmental and Bioresources Sciences, Jeonbuk National University, Iksan, Jeollabuk-do 54596, Republic of Korea
- Advanced Institute of Environment and Bioscience, College of Environmental and Bioresources Sciences, Jeonbuk National University, Iksan, Jeollabuk-do 54596, Republic of Korea
| | - Jongwon Yoon
- Jeonju Center, Korea Basic Science Institute, Jeonju, Jeollabuk-do 54907, Republic of Korea
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Steele JA, Lewis RA. Laser-induced oxidation kinetics of bismuth surface microdroplets on GaAsBi studied in situ by Raman microprobe analysis. Opt Express 2014; 22:32261-32275. [PMID: 25607191 DOI: 10.1364/oe.22.032261] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We report the cw-laser-induced oxidation of molecular-beam-epitaxy grown GaAsBi bismuth surface microdroplets investigated in situ by micro-Raman spectroscopy under ambient conditions as a function of irradiation power and time. Our results reveal the surface droplets are high-purity crystalline bismuth and the resultant Bi2O3 transformation to be β-phase and stable at room temperature. A detailed Raman study of Bi microdroplet oxidation kinetics yields insights into the laser-induced oxidation process and offers useful real-time diagnostics. The temporal evolution of new β-Bi2O3 Raman modes is shown to be well described by Johnson-Mehl-Avrami-Kolmogorov kinetic transformation theory and while this study limits itself to the laser-induced oxidation of GaAsBi bismuth surface droplets, the results will find application within the wider context of bismuth laser-induced oxidation and direct Raman laser processing.
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Kandiel TA, Anjum DH, Takanabe K. Nano-sized quaternary CuGa2In3S8 as an efficient photocatalyst for solar hydrogen production. ChemSusChem 2014; 7:3112-3121. [PMID: 25187083 DOI: 10.1002/cssc.201402525] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Revised: 07/14/2014] [Indexed: 06/03/2023]
Abstract
The synthesis of quaternary metal sulfide (QMS) nanocrystals is challenging because of the difficulty to control their stoichiometry and phase structure. Herein, quaternary CuGa2In3S8 photocatalysts with a primary particle size of ≈4 nm are synthesized using a facile hot-injection method by fine-tuning the sulfur source injection temperature and aging time. Characterization of the samples reveals that quaternary CuGa2In3S8 nanocrystals exhibit n-type semiconductor characteristics with a transition band gap of ≈1.8 eV. Their flatband potential is located at -0.56 V versus the standard hydrogen electrode at pH 6.0 and is shifted cathodically by 0.75 V in solutions with pH values greater than 12.0. Under optimized conditions, the 1.0 wt % Ru-loaded CuGa2In3S8 photocatalyst exhibits a photocatalytic H2 evolution response up to 700 nm and an apparent quantum efficiency of (6.9±0.5) % at 560 nm. These results indicate clearly that QMS nanocrystals have great potential as nano-photocatalysts for solar H2 production.
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Affiliation(s)
- Tarek A Kandiel
- Division of Physical Sciences and Engineering, KAUST Catalysis Center (KCC), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900 (Saudi Arabia); Department of Chemistry, Faculty of Science, Sohag University, Sohag 82524 (Egypt).
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Lee YJ, Yang ZP, Chen PG, Hsieh YA, Yao YC, Liao MH, Lee MH, Wang MT, Hwang JM. Monolithic integration of GaN-based light-emitting diodes and metal-oxide-semiconductor field-effect transistors. Opt Express 2014; 22 Suppl 6:A1589-95. [PMID: 25607316 DOI: 10.1364/oe.22.0a1589] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
In this study, we report a novel monolithically integrated GaN-based light-emitting diode (LED) with metal-oxide-semiconductor field-effect transistor (MOSFET). Without additionally introducing complicated epitaxial structures for transistors, the MOSFET is directly fabricated on the exposed n-type GaN layer of the LED after dry etching, and serially connected to the LED through standard semiconductor-manufacturing technologies. Such monolithically integrated LED/MOSFET device is able to circumvent undesirable issues that might be faced by other kinds of integration schemes by growing a transistor on an LED or vice versa. For the performances of resulting device, our monolithically integrated LED/MOSFET device exhibits good characteristics in the modulation of gate voltage and good capability of driving injected current, which are essential for the important applications such as smart lighting, interconnection, and optical communication.
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Pfeiffer M, Lindfors K, Zhang H, Fenk B, Phillipp F, Atkinson P, Rastelli A, Schmidt OG, Giessen H, Lippitz M. Eleven nanometer alignment precision of a plasmonic nanoantenna with a self-assembled GaAs quantum dot. Nano Lett 2014; 14:197-201. [PMID: 24341867 DOI: 10.1021/nl403730q] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Plasmonics offers the opportunity of tailoring the interaction of light with single quantum emitters. However, the strong field localization of plasmons requires spatial fabrication accuracy far beyond what is required for other nanophotonic technologies. Furthermore, this accuracy has to be achieved across different fabrication processes to combine quantum emitters and plasmonics. We demonstrate a solution to this critical problem by controlled positioning of plasmonic nanoantennas with an accuracy of 11 nm next to single self-assembled GaAs semiconductor quantum dots, whose position can be determined with nanometer precision. These dots do not suffer from blinking or bleaching or from random orientation of the transition dipole moment as colloidal nanocrystals do. Our method introduces flexible fabrication of arbitrary nanostructures coupled to single-photon sources in a controllable and scalable fashion.
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Affiliation(s)
- Markus Pfeiffer
- Max Planck Institute for Solid State Research , Heisenbergstrasse 1, D-70569 Stuttgart, Germany
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Jeon JH, Seo SB, Park HS, Choe HH, Seo JH, Park KC, Park SHK. Negative gate bias and light illumination-induced hump in amorphous InGaZnO thin film transistor. J Nanosci Nanotechnol 2013; 13:7535-7539. [PMID: 24245287 DOI: 10.1166/jnn.2013.7895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
While observing the transfer characteristics of a-IGZO TFTs, it was noticed that a hump occurred in the subthreshold regime after light and bias stress. This study analyzes the mechanism of the hump occurrence. It was determined that hump characteristics were related with parasitic TFTs which formed at the peripheral edges parallel with the channel direction. It seems that the negative shift of the transfer characteristics of parasitic TFTs was larger than that of the main TFT under light and bias stress. Therefore, the difference in the negative shift between the main TFT and the parasitic TFT was the origin of the hump occurrence. We investigated the instability of a-IGZO TFTs under negative gate bias with light illumination for various channel structures in order to verify the above mechanism.
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Affiliation(s)
- Jae-Hong Jeon
- School of Electronics, Telecommunications and Computer Engineering, Korea Aerospace University, Goyang, 412-791, Korea
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Biswas T, Ghosh TK. Phonon-drag magnetothermopower in Rashba spin-split two-dimensional electron systems. J Phys Condens Matter 2013; 25:415301. [PMID: 24047679 DOI: 10.1088/0953-8984/25/41/415301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We study the phonon-drag contribution to the thermoelectric power in a quasi-two-dimensional electron system confined in GaAs/AlGaAs heterostructure in the presence of both Rashba spin-orbit interaction and perpendicular magnetic field at very low temperature. It is observed that the peaks in the phonon-drag thermopower split into two when the Rashba spin-orbit coupling constant is strong. This splitting is a direct consequence of the Rashba spin-orbit interaction. We show the dependence of phonon-drag thermopower on both magnetic field and temperature numerically. A power-law dependence of phonon-drag magnetothermopower on the temperature in the Bloch-Gruneisen regime is found. We also extract the exponent of the temperature dependence of phonon-drag thermopower for different parameters like electron density, magnetic field, and the spin-orbit coupling constant.
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Affiliation(s)
- Tutul Biswas
- Department of Physics, Indian Institute of Technology-Kanpur, Kanpur-208 016, India
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8
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Yang T, Wang X, Liu W, Shi Y, Yang F. Double-layer anti-reflection coating containing a nanoporous anodic aluminum oxide layer for GaAs solar cells. Opt Express 2013; 21:18207-18215. [PMID: 23938691 DOI: 10.1364/oe.21.018207] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Multilayer anti-reflection (AR) coatings can be used to improve the efficiency of Gallium Arsenide (GaAs) solar cells. We propose an alternate method to obtain optical thin films with specified refractive indices, which is using a self-assembled nanoporous anodic aluminum oxide (AAO) template as an optical thin film whose effective refractive index can be tuned by pore-widening. Different kinds of double-layer AR coatings each containing an AAO layer were designed and investigated by finite difference time domain (FDTD) method. We demonstrate that a λ /4n - λ /4n AR coating consisting of a TiO(2) layer and an AAO layer whose effective refractive index is 1.32 realizes a 96.8% light absorption efficiency of the GaAs solar cell under AM1.5 solar spectrum (400 nm-860 nm). We also have concluded some design principles of the double-layer AR coating containing an AAO layer for GaAs solar cells.
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Affiliation(s)
- Tianshu Yang
- Engineering Research Center for Semiconductor Integrated Technology, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
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9
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Mittendorff M, Xu M, Dietz RJB, Künzel H, Sartorius B, Schneider H, Helm M, Winnerl S. Large area photoconductive terahertz emitter for 1.55 μm excitation based on an InGaAs heterostructure. Nanotechnology 2013; 24:214007. [PMID: 23619031 DOI: 10.1088/0957-4484/24/21/214007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We present scalable large area terahertz (THz) emitters based on a nanoscale multilayer InGaAs/InAlAs heterostructure and a microstructured electrode pattern. The emitters are designed for pump lasers working at the telecommunication wavelength of 1.55 μm. Electric THz fields of more than 2.5 V cm⁻¹ are reached with moderate pump powers of 80 mW, the corresponding spectrum extends up to 3 THz. The saturation characteristics have been investigated for different pump laser spot sizes. For small pump powers of less than 50 mW the emitted THz field is nearly independent of the spot size, for higher pump powers and small spot sizes a clear saturation of the generated THz pulse can be observed. Hence the use of scalable emitters is especially promising for high power fibre laser systems. The spectral content of the generated radiation is nearly independent of the parameters spot size, pump power, and bias voltage, which allows for stable operation in spectroscopic applications.
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Affiliation(s)
- Martin Mittendorff
- Helmholtz-Zentrum Dresden-Rossendorf, PO Box 510119, D-01314 Dresden, Germany.
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Joyce HJ, Docherty CJ, Gao Q, Tan HH, Jagadish C, Lloyd-Hughes J, Herz LM, Johnston MB. Electronic properties of GaAs, InAs and InP nanowires studied by terahertz spectroscopy. Nanotechnology 2013; 24:214006. [PMID: 23619012 DOI: 10.1088/0957-4484/24/21/214006] [Citation(s) in RCA: 107] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We have performed a comparative study of ultrafast charge carrier dynamics in a range of III-V nanowires using optical pump-terahertz probe spectroscopy. This versatile technique allows measurement of important parameters for device applications, including carrier lifetimes, surface recombination velocities, carrier mobilities and donor doping levels. GaAs, InAs and InP nanowires of varying diameters were measured. For all samples, the electronic response was dominated by a pronounced surface plasmon mode. Of the three nanowire materials, InAs nanowires exhibited the highest electron mobilities of 6000 cm² V⁻¹ s⁻¹, which highlights their potential for high mobility applications, such as field effect transistors. InP nanowires exhibited the longest carrier lifetimes and the lowest surface recombination velocity of 170 cm s⁻¹. This very low surface recombination velocity makes InP nanowires suitable for applications where carrier lifetime is crucial, such as in photovoltaics. In contrast, the carrier lifetimes in GaAs nanowires were extremely short, of the order of picoseconds, due to the high surface recombination velocity, which was measured as 5.4 × 10⁵ cm s⁻¹. These findings will assist in the choice of nanowires for different applications, and identify the challenges in producing nanowires suitable for future electronic and optoelectronic devices.
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Affiliation(s)
- Hannah J Joyce
- Department of Physics, University of Oxford, Clarendon Laboratory, Oxford OX1 3PU, UK.
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Sahin D, Gaggero A, Hoang TB, Frucci G, Mattioli F, Leoni R, Beetz J, Lermer M, Kamp M, Höfling S, Fiore A. Integrated autocorrelator based on superconducting nanowires. Opt Express 2013; 21:11162-11170. [PMID: 23669973 DOI: 10.1364/oe.21.011162] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We demonstrate an integrated autocorrelator based on two superconducting single-photon detectors patterned on top of a GaAs ridge waveguide. This device enables the on-chip measurement of the second-order intensity correlation function g(2)(τ). A polarization-independent device quantum efficiency in the 1% range is reported, with a timing jitter of 88 ps at 1300 nm. g(2)(τ) measurements of continuous-wave and pulsed laser excitations are demonstrated with no measurable crosstalk within our measurement accuracy.
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Affiliation(s)
- Döndü Sahin
- COBRA Research Institute, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands.
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12
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Kim SJ, Kim KH, Kim TG. Improved performance of GaN-based vertical light emitting diodes with conducting and transparent single-walled carbon nanotube networks. Opt Express 2013; 21:8062-8068. [PMID: 23571896 DOI: 10.1364/oe.21.008062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
In this study, reduced forward voltage and improved light output power of GaN-based vertical light-emitting diodes (VLEDs) incorporating single-walled carbon nanotube (SWNT)-networks is reported. The SWNT-networks were directly formed on a roughened (textured) n-GaN surface via a solution-processed dip-coating method. The surface-roughened VLEDs with the proposed SWNT-networks had a forward voltage of 3.84 V at 350 mA, lower than that of the surface-roughened VLEDs, and exhibited an increase in light output power by 12.9% at 350 mA compared to the surface-roughened VLEDs. These improved electrical and optical properties could be attributed to the SWNT-networks put on the roughened n-GaN surface, which increase the lateral current transport and create scattering of light through the formation of additional roughness.
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Affiliation(s)
- Su Jin Kim
- School of Electrical Engineering, Korea University, Seoul 136-701, South Korea
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Wang TY, Ou SL, Shen KC, Wuu DS. Effect of non-vacuum thermal annealing on high indium content InGaN films deposited by pulsed laser deposition. Opt Express 2013; 21:7337-7342. [PMID: 23546117 DOI: 10.1364/oe.21.007337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
InGaN films with 33% and 60% indium contents were deposited by pulsed laser deposition (PLD) at a low growth temperature of 300 °C. The films were then annealed at 500-800 °C in the non-vacuum furnace for 15 min with an addition of N(2) atmosphere. X-ray diffraction results indicate that the indium contents in these two films were raised to 41% and 63%, respectively, after annealing in furnace. In(2)O(3) phase was formed on InGaN surface during the annealing process, which can be clearly observed by the measurements of auger electron spectroscopy, transmission electron microscopy and x-ray photoelectron spectroscopy. Due to the obstruction of indium out-diffusion by forming In(2)O(3) on surface, it leads to the efficient increment in indium content of InGaN layer. In addition, the surface roughness was greatly improved by removing In(2)O(3) with the etching treatment in HCl solution. Micro-photoluminescence measurement was performed to analyze the emission property of InGaN layer. For the as-grown InGaN with 33% indium content, the emission wavelength was gradually shifted from 552 to 618 nm with increasing the annealing temperature to 800 °C. It reveals the InGaN films have high potential in optoelectronic applications.
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Affiliation(s)
- Tzu-Yu Wang
- Department of Materials Science and Engineering, National Chung Hsing University, Taichung 402, Taiwan
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Liu F, Yan W, Chuang YJ, Zhen Z, Xie J, Pan Z. Photostimulated near-infrared persistent luminescence as a new optical read-out from Cr³⁺-doped LiGa₅O₈. Sci Rep 2013; 3:1554. [PMID: 23532003 PMCID: PMC3609016 DOI: 10.1038/srep01554] [Citation(s) in RCA: 146] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Accepted: 03/08/2013] [Indexed: 11/25/2022] Open
Abstract
In conventional photostimulable storage phosphors, the optical information written by x-ray or ultraviolet irradiation is usually read out as a visible photostimulated luminescence (PSL) signal under the stimulation of a low-energy light with appropriate wavelength. Unlike the transient PSL, here we report a new optical read-out form, photostimulated persistent luminescence (PSPL) in the near-infrared (NIR), from a Cr(3+)-doped LiGa₅O₈ NIR persistent phosphor exhibiting a super-long NIR persistent luminescence of more than 1,000 h. An intense PSPL signal peaking at 716 nm can be repeatedly obtained in a period of more than 1,000 h when an ultraviolet-light (250-360 nm) pre-irradiated LiGa₅O₈:Cr(3+) phosphor is repeatedly stimulated with a visible light or a NIR light. The LiGa₅O₈:Cr(3+) phosphor has promising applications in optical information storage, night-vision surveillance, and in vivo bio-imaging.
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Affiliation(s)
- Feng Liu
- College of Engineering, University of Georgia, Athens, GA 30602, USA
- Department of Physics and Astronomy, University of Georgia, Athens, GA 30602, USA
| | - Wuzhao Yan
- College of Engineering, University of Georgia, Athens, GA 30602, USA
- Department of Physics and Astronomy, University of Georgia, Athens, GA 30602, USA
| | - Yen-Jun Chuang
- College of Engineering, University of Georgia, Athens, GA 30602, USA
| | - Zipeng Zhen
- Department of Chemistry, University of Georgia, Athens, GA 30602, USA
| | - Jin Xie
- Department of Chemistry, University of Georgia, Athens, GA 30602, USA
| | - Zhengwei Pan
- College of Engineering, University of Georgia, Athens, GA 30602, USA
- Department of Physics and Astronomy, University of Georgia, Athens, GA 30602, USA
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Fan P, Colombo C, Huang KCY, Krogstrup P, Nygård J, Fontcuberta I Morral A, Brongersma ML. An electrically-driven GaAs nanowire surface plasmon source. Nano Lett 2012; 12:4943-4947. [PMID: 22924961 DOI: 10.1021/nl302521v] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Over the past decade, the properties of plasmonic waveguides have extensively been studied as key elements in important applications that include biosensors, optical communication systems, quantum plasmonics, plasmonic logic, and quantum-cascade lasers. Whereas their guiding properties are by now fairly well-understood, practical implementation in chipscale systems is hampered by the lack of convenient electrical excitation schemes. Recently, a variety of surface plasmon lasers have been realized, but they have not yet been waveguide-coupled. Planar incoherent plasmonic sources have recently been coupled to plasmonic guides but routing of plasmonic signals requires coupling to linear waveguides. Here, we present an experimental demonstration of electrically driven GaAs nanowire light sources integrated with plasmonic nanostrip waveguides with a physical cross-section of 0.08λ(2). The excitation and waveguiding of surface plasmon-polaritons (SPPs) is experimentally demonstrated and analyzed with the help of full-field electromagnetic simulations. Splitting and routing of the electrically generated SPP signals around 90° bends are also shown. The realization of integrated plasmon sources greatly increases the applicability range of plasmonic waveguides and routing elements.
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Affiliation(s)
- Pengyu Fan
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, United States
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Parker JS, Sivananthan A, Norberg E, Coldren LA. Regrowth-free high-gain InGaAsP/InP active-passive platform via ion implantation. Opt Express 2012; 20:19946-19955. [PMID: 23037047 DOI: 10.1364/oe.20.019946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We demonstrate a regrowth-free material platform to create monolithic InGaAsP/InP photonic integrated circuits (PICs) with high-gain active and low-loss passive sections via a PL detuning of >135 nm. We show 2.5 µm wide by 400 µm long semiconductor optical amplifiers with >40 dB/mm gain at 1570 nm, and passive waveguide losses <2.3 dB/mm. The bandgap in the passive section is detuned using low-energy 190 keV channelized phosphorous implantation and subsequent rapid thermal annealing to achieve impurity-induced quantum well intermixing (QWI). The PL wavelengths in the active and passive sections are 1553 and 1417 nm, respectively. Lasing wavelengths for 500 µm Fabry-Perot lasers are 1567 and 1453 nm, respectively.
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Affiliation(s)
- John S Parker
- Electrical and Computer Engineering Department, University of California at Santa Barbara, Santa Barbara, CA 93106, USA.
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Liu N, Tian W, Zhang X, Su J, Zhang Q, Gao Y. Enhancement of ultraviolet detecting by coupling the photoconductive behavior of GaN nanowires and p-n junction. Opt Express 2012; 20:20748-20753. [PMID: 23037124 DOI: 10.1364/oe.20.020748] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The giant improvement of ultraviolet response behavior of a conventional GaN p-n film structured detector by the incorporation of slanted GaN nanowires is reported. The GaN nanowires/p-n film structure shows great photoresponse performance, exhibiting a short response time <0.1 s and a high sensitivity, being stable and reproducible with an on/off current contrast ratio as high as 1800 at zero bias under 365 nm ultraviolet light irradiation. Via carefully analyzing the experiment result and the band diagram of the device, the enhancement can be predominantly attributed to the photogenerated electrons in the slanted GaN nanowires.
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Affiliation(s)
- Nishuang Liu
- Wuhan National Laboratory for Optoelectronics (WNLO), School of Physics, Huazhong University of Science and Technology (HUST), Luoyu Road 1037, Wuhan 430074, China
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Natrella M, Rouvalis E, Liu CP, Liu H, Renaud CC, Seeds AJ. InGaAsP-based uni-travelling carrier photodiode structure grown by solid source molecular beam epitaxy. Opt Express 2012; 20:19279-19288. [PMID: 23038569 DOI: 10.1364/oe.20.019279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We report the first InGaAsP-based uni-travelling carrier photodiode structure grown by Solid Source Molecular Beam Epitaxy; the material contains layers of InGaAsP as thick as 300 nm and a 120 nm thick InGaAs absorber. Large area vertically illuminated test devices have been fabricated and characterised; the devices exhibited 0.1 A/W responsivity at 1550 nm, 12.5 GHz -3 dB bandwidth and -5.8 dBm output power at 10 GHz for a photocurrent of 4.8 mA. The use of Solid Source Molecular Beam Epitaxy enables the major issue associated with the unintentional diffusion of zinc in Metal Organic Vapour Phase Epitaxy to be overcome and gives the benefit of the superior control provided by MBE growth techniques without the costs and the risks of handling toxic gases of Gas Source Molecular Beam Epitaxy.
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Affiliation(s)
- Michele Natrella
- Department of Electronic & Electrical Engineering, University College London, Torrington Place, London, UK
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Danilov YA, Vikhrova OV, Kudrin AV, Zvonkov BN. Ferromagnetic GaAs structures with single Mn delta-layer fabricated using laser deposition. J Nanosci Nanotechnol 2012; 12:5122-5124. [PMID: 22905589 DOI: 10.1166/jnn.2012.4895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The new technique combining metal-organic chemical vapor epitaxy with laser ablation of solid targets was used for fabrication of ferromagnetic GaAs structures with single Mn delta-doped layer. The structures demonstrated anomalous Hall effect, planar Hall effect, negative and anisotropic magnetoresistance in temperature range of 10-35 K. In GaAs structures with only single Mn delta-layer (without additional 2D hole gas channel or quantum well) ferromagnetism was observed for the first time.
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Affiliation(s)
- Yuri A Danilov
- Physico-Technical Research Institute of University of Nizhny Novgorod, 23/3 Gagarine Ave., 603950, Nizhny Novgorod, Russian Federation
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20
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Hwang YJ, Wu CH, Hahn C, Jeong HE, Yang P. Si/InGaN core/shell hierarchical nanowire arrays and their photoelectrochemical properties. Nano Lett 2012; 12:1678-1682. [PMID: 22369381 DOI: 10.1021/nl3001138] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Three-dimensional hierarchical nanostructures were synthesized by the halide chemical vapor deposition of InGaN nanowires on Si wire arrays. Single phase InGaN nanowires grew vertically on the sidewalls of Si wires and acted as a high surface area photoanode for solar water splitting. Electrochemical measurements showed that the photocurrent density with hierarchical Si/InGaN nanowire arrays increased by 5 times compared to the photocurrent density with InGaN nanowire arrays grown on planar Si (1.23 V vs RHE). High-resolution transmission electron microscopy showed that InGaN nanowires are stable after 15 h of illumination. These measurements show that Si/InGaN hierarchical nanostructures are a viable high surface area electrode geometry for solar water splitting.
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Affiliation(s)
- Yun Jeong Hwang
- Department of Chemistry, University of California, Berkeley, California 94720, USA
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21
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Cui K, Fathololoumi S, Golam Kibria M, Botton GA, Mi Z. Molecular beam epitaxial growth and characterization of catalyst-free InN/InxGa1-xN core/shell nanowire heterostructures on Si(111) substrates. Nanotechnology 2012; 23:085205. [PMID: 22293649 DOI: 10.1088/0957-4484/23/8/085205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We report on the achievement of, for the first time, InN/InGaN core/shell nanowire heterostructures, which are grown directly on Si(111) substrates by plasma-assisted molecular beam epitaxy. The crystalline quality of the heterostructures is confirmed by transmission electron microscopy, and the elemental mapping through energy dispersive x-ray spectrometry further reveals the presence of an InGaN shell covering the sidewall and top regions of the InN core. The optical characterizations reveal two emission peaks centered at ∼1685 nm and 1845 nm at 5 K, which are related to the emission from the InGaN shell and InN core, respectively. The InN/InGaN core/shell nanoscale heterostructures exhibit a very high internal quantum efficiency of ∼62% at room temperature, which is attributed to the strong carrier confinement provided by the InGaN shell as well as the nearly intrinsic InN core.
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Affiliation(s)
- Kai Cui
- Department of Electrical and Computer Engineering, McGill University, 3480 University Street, Montreal, QC, Canada
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22
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Butun S, Cinel NA, Ozbay E. Nanoantenna coupled UV subwavelength photodetectors based on GaN. Opt Express 2012; 20:2649-2656. [PMID: 22330502 DOI: 10.1364/oe.20.002649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The integration of nano structures with opto-electronic devices has many potential applications. It allows the coupling of more light into or out of the device while decreasing the size of the device itself. Such devices are reported in the VIS and NIR regions. However, making plasmonic structures for the UV region is still a challenge. Here, we report on a UV nano-antenna integrated metal semiconductor metal (MSM) photodetector based on GaN. We designed and fabricated Al grating structures. Well defined plasmonic resonances were measured in the reflectance spectra. Optimized grating structure integrated photodetectors exhibited more than sevenfold photocurrent enhancement. Finite difference time domain simulations revealed that both geometrical and plasmonic effects played role in photocurrent enhancement.
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Affiliation(s)
- Serkan Butun
- Nanotechnology Research Center, Bilkent University, Bilkent, 06800 Ankara, Turkey.
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Abstract
We report on the photocurrent behavior of single GaN n-i-n nanowires (NWs) grown by plasma-assisted molecular-beam epitaxy on Si(111). These structures present a photoconductive gain in the range of 10(5)-10(8) and an ultraviolet (350 nm) to visible (450 nm) responsivity ratio larger than 6 orders of magnitude. Polarized light couples with the NW geometry with a maximum photoresponse for polarization along the NW axis. The photocurrent scales sublinearly with optical power, following a I ~ P(β) law (β < 1) in the measured range with β increasing with the measuring frequency. The photocurrent time response remains in the millisecond range, which is in contrast to the persistent (hours) photoconductivity effects observed in two-dimensional photoconductors. The photocurrent is independent of the measuring atmosphere, either in the air or in vacuum. Results are interpreted taking into account the effect of surface states and the total depletion of the NW intrinsic region.
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Affiliation(s)
- F González-Posada
- CEA-CNRS Group Nanophysique et Semiconducteurs, INAC-SP2M, CEA-Grenoble, 17 rue des Martyrs, 38054 Grenoble Cedex 9, France.
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24
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Hernández-Mínguez A, Möller M, Breuer S, Pfüller C, Somaschini C, Lazić S, Brandt O, García-Cristóbal A, de Lima MM, Cantarero A, Geelhaar L, Riechert H, Santos PV. Acoustically driven photon antibunching in nanowires. Nano Lett 2012; 12:252-258. [PMID: 22142481 DOI: 10.1021/nl203461m] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The oscillating piezoelectric field of a surface acoustic wave (SAW) is employed to transport photoexcited carriers, as well as to spatially control exciton recombination in GaAs-based nanowires (NWs) on a subns time scale. The experiments are carried out in core-shell NWs transferred to a SAW delay line on a LiNbO(3) crystal. Carriers generated in the NW by a focused laser spot are acoustically transferred to a second location, leading to the remote emission of subns light pulses synchronized with the SAW phase. The dynamics of the carrier transport, investigated using spatially and time-resolved photoluminescence, is well-reproduced by computer simulations. The high-frequency contactless manipulation of carriers by SAWs opens new perspectives for applications of NWs in opto-electronic devices operating at gigahertz frequencies. The potential of this approach is demonstrated by the realization of a high-frequency source of antibunched photons based on the acoustic transport of electrons and holes in (In,Ga)As NWs.
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Affiliation(s)
- A Hernández-Mínguez
- Paul-Drude-Institut für Festkörperelektronik, Hausvogteiplatz 5-7, 10117 Berlin, Germany.
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25
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Sadakuni S, Murata J, Yagi K, Sano Y, Okamoto T, Kenta A, Hattori AN, Yamauchi K. Efficient wet etching of GaN (0001) substrate with subsurface damage layer. J Nanosci Nanotechnol 2011; 11:2979-2982. [PMID: 21776664 DOI: 10.1166/jnn.2011.3897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Photoenhanced chemical (PEC) etching is applicable for processing an n-GaN (0001) surface rapidly. In this process, the surface oxidation is enhanced by photo-generated holes and the resulting oxide can dissolve into solutions. In current work, we conduct bias-assisted PEC etching in a KOH solution with a positively biased wafer, to remove the crystallographically highly damaged layer. The employed substrate was mechanically polished with diamond slurry of sub-micrometer particle size. Without the positive bias, the rate of PEC etching was quite low because the photogenerated holes were quickly depleted by the recombination process at the crystallographic defects and they could not contribute to the oxidation. On the other hand, in the case where the bias was applied, the photogenerated holes and electrons are separated forcibly in the band-bended surface, which effectively contributed to surface oxidation. As a result, a high removal rate was realized even on the damaged surface.
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Affiliation(s)
- Shun Sadakuni
- Department of Precision Science and Technology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
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26
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Hsu KY, Wang CY, Liu CP. Growth and characteristics of self-assembly defect-free GaN surface islands by molecular beam epitaxy. J Nanosci Nanotechnol 2011; 11:3393-3398. [PMID: 21776715 DOI: 10.1166/jnn.2011.3752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
GaN surface nano-islands of high crystal quality, without any dislocations or other extended defects, are grown on a c-plane sapphire substrate by plasma-assisted molecular beam epitaxy. Nano-island growth requires special conditions in terms of V/III ratio and substrate temperature, distinct from either film or nanocolumn growth. The insertion of a nitrided Ga layer can effectively improve the uniformity of the nano-islands in both shape and size. The islands are well faced truncated pyramids with island size ranged from 30 to 110 nm, and height ranged from 30 to 55 nm. On, the other hand, the density and facet of the GaN surface islands would be affected by the growth conditions. An increase of the V/III ratio from 30 to 40 led to an increase in density from 1.4 x 10(9) to 4.3 x 10(9) cm(-2) and an evolution from {1-21-1} facets to {1-21-2} facets. The GaN layers containing the surface islands can moderate the compressive strain due to the lattice and thermal mismatch between GaN and c-sapphire. Conductive atomic force microscopy shows that the off-axis sidewall facets are more electrically active than those at the island center. The formation of the GaN surface islands is strongly induced by the Ehrlich-Schwoebel barrier effect of preexisting islands grown in the early growth stage. GaN surface islands are ideal templates for growing nano-devices.
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Affiliation(s)
- Kuang-Yuan Hsu
- Department of Materials Science and Engineering, National Cheng Kung University, Tainan 70101, Taiwan, Republic of China
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27
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Li L, Auer E, Liao M, Fang X, Zhai T, Gautam UK, Lugstein A, Koide Y, Bando Y, Golberg D. Deep-ultraviolet solar-blind photoconductivity of individual gallium oxide nanobelts. Nanoscale 2011; 3:1120-1126. [PMID: 21203645 DOI: 10.1039/c0nr00702a] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We designed solar-blind deep-ultraviolet semiconductor photodetectors using individual Ga2O3 nanobelts. The photoconductive behavior was systematically studied. The photodetectors demonstrate high selectivity towards 250 nm light, fast response times of less than 0.3 s, and a large photocurrent to dark current ratio of up to 4 orders of magnitude. The photoresponse parameters such as photocurrent, response time, and quantum efficiency depend strongly on the intensity of light, the detector environment, and the nanobelt size. The photoresponse mechanism was discussed, which was mainly attributed to the band bending, surface traps, and distribution of traps in the bandgap. Present Ga2O3 nanobelts can be exploited for future applications in photo sensing, light-emitting diodes, and optical switches.
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Affiliation(s)
- Liang Li
- International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), Namiki 1-1, Tsukuba, Ibaraki 305-0044, Japan.
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28
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Ren S, Zhao N, Crawford SC, Tambe M, Bulović V, Gradecak S. Heterojunction photovoltaics using GaAs nanowires and conjugated polymers. Nano Lett 2011; 11:408-413. [PMID: 21171629 DOI: 10.1021/nl1030166] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We demonstrate an organic/inorganic solar cell architecture based on a blend of poly(3-hexylthiophene) (P3HT) and narrow bandgap GaAs nanowires. The measured increase of device photocurrent with increased nanowire loading is correlated with structural ordering within the active layer that enhances charge transport. Coating the GaAs nanowires with TiO(x) shells passivates nanowire surface states and further improves the photovoltaic performance. We find that the P3HT/nanowire cells yield power conversion efficiencies of 2.36% under white LED illumination for devices containing 50 wt % of TiO(x)-coated GaAs nanowires. Our results constitute important progress for the use of nanowires in large area solution processed hybrid photovoltaic cells and provide insight into the role of structural ordering in the device performance.
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Affiliation(s)
- Shenqiang Ren
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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29
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Henneghien AL, Tourbot G, Daudin B, Lartigue O, Désières Y, Gérard JM. Optical anisotropy and light extraction efficiency of MBE grown GaN nanowires epilayers. Opt Express 2011; 19:527-539. [PMID: 21263592 DOI: 10.1364/oe.19.000527] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The use of nanowires as active medium seems very promising for the development of high brightness LEDs. With a lower effective refractive index than bulk, semiconductor nanowire layers may lead to a high light extraction efficiency. We hereafter discuss the anisotropic properties of dense arrays of molecular beam epitaxy (MBE) grown gallium nitride (GaN) nanowires and the consequences on the optical design of nanowire based LEDs. In particular we show numerically that light extraction efficiency as high as 72% can be expected for GaN nanowires layer grown on a low cost Si substrate.
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30
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Abstract
We demonstrate Au-nanoparticle-assisted random lasing from a powdered GaN sample. In the presence of Au nanoparticles on GaN powder surfaces, several lasing lines are observed in photoexcited luminescence spectra near the center of the GaN band-edge emission peak. The random lasing is considered to arise from a decrease in the lasing threshold due to the suppression of crystal defect loss by surface plasmon excitation on Au. From spatially resolved lasing emission spectra and their FT analysis results, the formation of random lasing cavities at different spatial positions is confirmed. The size of the random lasing spot is determined to be larger than that of the scattered light speckle of the pumping source on a thin powdered GaN sample.
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31
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Chiba D, Matsukura F, Ohno H. Electrically defined ferromagnetic nanodots. Nano Lett 2010; 10:4505-4508. [PMID: 20923162 DOI: 10.1021/nl102379h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
While ferromagnetic nanodots are being widely studied from fundamental as well as application points of views, so far all the dots have been physically defined; once made, one cannot change their dimension or size. We show that ferromagnetic nanodots can be electrically defined. To realize this, we utilize an electric field to modulate the in-plane distribution of carriers in a ferromagnetic semiconductor (Ga,Mn)As film with a meshed gate structure having a large number of nanoscaled windows.
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Affiliation(s)
- Daichi Chiba
- Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
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32
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Mialichi JR, Camposeo A, Persano L, Barea LAM, Del Carro P, Pisignano D, Frateschi NC. Hybrid planar microresonators with organic and InGaAs active media. Opt Express 2010; 18:11650-11656. [PMID: 20589023 DOI: 10.1364/oe.18.011650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The authors report on the fabrication of hybrid planar micro-resonators based on InGaAs microdisks with an evaporated organic material. Samples of InGaAs grown on InP(100) substrates are obtained by Chemical Beam Epitaxy, and microdisks of InGaAs with different diameters are fabricated by focused ion beam. The hybrid disks are obtained by the subsequent evaporation of 8-hydroxyquinoline aluminium doped with 4-Dicyanomethylene-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran on the InGaAs microdisks. The devices, characterized by micro- and confocal photoluminescence imaging and spectroscopy, exhibit emission around 650 nm, from the organic material for disks with different radius. Finally, simultaneous emission in the visible and at whispering gallery resonant modes in the 1350-1450 nm range are observed due to excitation transfer to InGaAs. These devices open the possibility to combine the flexibility of organics with the high gain of III-V compounds for wavelength down conversion and telecom applications.
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Affiliation(s)
- J R Mialichi
- Device Research Laboratory, Applied Physics Department, Gleb Wataghin Physics Institute, University of Campinas-UNICAMP, 13083-970 Campinas, São Paulo, Brazil.
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33
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Ruppert C, Thunich S, Abstreiter G, Fontcuberta i Morral A, Holleitner AW, Betz M. Quantum interference control of femtosecond, microA current bursts in single GaAs nanowires. Nano Lett 2010; 10:1799-1804. [PMID: 20373775 DOI: 10.1021/nl1004898] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
A phase-stable superposition of femtosecond pulses from a compact erbium-doped fiber source and their second harmonic is shown to induce ultrashort approximately microA current bursts in single unbiased GaAs nanowires. Current injection relies on a quantum interference of one- and two-photon absorption pathways. The vector direction of the current is solely dictated by the polarization and relative phase of the harmonically related light components while its power dependence is consistent with a third order optical nonlinearity.
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Affiliation(s)
- C Ruppert
- Physik-Department E11, Technische Universität München, Garching, Germany
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Abstract
InGaP nanowires (NWs) were grown by the Au-assisted method in a gas source molecular beam epitaxy system. The dependence of InGaP composition, morphology and stacking fault density was studied with respect to group III and V impingement rate and size of the Au particle. Compositional analysis showed that the NWs had an In-rich core and a Ga-rich shell structure. The In incorporation within the NW became limited as the Au seed particle size diminished or the group III and V flux decreased. The NWs had wurtzite (WZ) crystal structure with zinc blende (ZB) segments (stacking faults). The density of the stacking faults decreased as the group III flux decreased and the group V flux increased.
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Affiliation(s)
- A Fakhr
- Department of Electrical and Computer Engineering, McMaster University, Hamilton, ON, L8S 4K1, Canada
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35
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Abstract
InGaAs PIN photodetectors heterogeneously integrated on silicon-on-insulator waveguides are fabricated and characterized. Efficient evanescent coupling between silicon-on-insulator waveguides and InGaAs photodetectors is achieved. The fabricated photodetectors can work well without external bias and have a very low dark current of 10pA. The measured responsivity of a 40microm-long photodetector is 1.1A/W (excluding the coupling loss between the fiber and the SOI waveguide) at a wavelength of 1550nm and shows good linearity for an input power range of 40dB. Due to the large absorption coefficient of InGaAs and the efficient evanescent coupling, the fabricated photodetectors can cover the whole S, C and L communication bands.
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Affiliation(s)
- Zhen Sheng
- INTEC Department, Photonics Research Group, Ghent University-IMEC, Gent, Belgium.
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36
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Abstract
The InGaZnO thin films are fabricated on the quartz glass using pulsed laser deposition (PLD), where the target is prepared by mixing the Ga(2)O(3), In(2)O(3), and ZnO powders at a mol ratio of 1:1:8 before the solid-state reactions in a tube furnace at the atmospheric pressure. The product thin films were characterized comprehensively by X-ray diffraction, atomic force microscopy, Hall-effect investigation, and X-ray photoelectron spectroscopy. Thus, we demonstrate semiconductor thin-film materials with high smoothness, high transmittance in visible region, and excellent electrical properties.
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Affiliation(s)
- Jiangbo Chen
- College of Applied Sciences, Beijing University of technology, Beijing, China
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37
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Feldmeier C, Abiko M, Schwarz UT, Kawakami Y, Micheletto R. Transient memory effect in the photoluminescence of InGaN single quantum wells. Opt Express 2009; 17:22855-22860. [PMID: 20052211 DOI: 10.1364/oe.17.022855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The transition to maximum photoluminescence of InGaN single quantum wells is a phenomena that has time constants in the range of few seconds. Using a systematic illumination/darkening procedure we found that these characteristics are related to previous stimulations as if the sample has a memory of past illumination events. Choosing opportune time sequences, time constants were observed to vary more than 100%. These facts suggest the presence of carrier trapping/de-trapping processes that act beyond the single illumination event, accumulating over time in a complex effect.
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Affiliation(s)
- Christian Feldmeier
- Yokohama City University, Graduate School of Nanobioscience, Department of Nanosystem Science, 22-2 Seto Kanazawa-ku, 236-0027 Yokohama, Japan
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38
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Borschel C, Niepelt R, Geburt S, Gutsche C, Regolin I, Prost W, Tegude FJ, Stichtenoth D, Schwen D, Ronning C. Alignment of semiconductor nanowires using ion beams. Small 2009; 5:2576-2580. [PMID: 19714732 DOI: 10.1002/smll.200900562] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Gallium arsenide nanowires are grown on 100 GaAs substrates, adopting the epitaxial relation and thus growing with an angle around 35 degrees off the substrate surface. These straight nanowires are irradiated with different kinds of energetic ions. Depending on the ion species and energy, downwards or upwards bending of the nanowires is observed to increase with ion fluence. In the case of upwards bending, the nanowires can be aligned towards the ion beam direction at high fluences. Defect formation (vacancies and interstitials) within the implantation cascade is identified as the key mechanism for bending. Monte Carlo simulations of the implantation are presented to substantiate the results.
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Affiliation(s)
- Christian Borschel
- Institute for Solid State Physics, University of Jena, Max-Wien-Platz 1, 07743 Jena, Germany.
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39
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Collins D, Jarjour A, Hadjipanayi M, Taylor R, Oliver R, Kappers M, Humphreys C, Tahraoui A. Two-photon autocorrelation measurements on a single InGaN/GaN quantum dot. Nanotechnology 2009; 20:245702. [PMID: 19471082 DOI: 10.1088/0957-4484/20/24/245702] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We report on the use of interferometric autocorrelation measurements to investigate the non-linear absorption processes evident in single InGaN/GaN quantum dots. The near quadratic excitation intensity dependence of the photoluminescence signal in conjunction with the asymmetric collinear autocorrelation trace unambiguously confirms the process as being one involving two photons via an intermediate virtual state. These results highlight the inherently non-linear optical properties of these structures.
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Affiliation(s)
- Daniel Collins
- Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, UK
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40
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Su FH, Blanchard F, Sharma G, Razzari L, Ayesheshim A, Cocker TL, Titova LV, Ozaki T, Kieffer JC, Morandotti R, Reid M, Hegmann FA. Terahertz pulse induced intervalley scattering in photoexcited GaAs. Opt Express 2009; 17:9620-9629. [PMID: 19506611 DOI: 10.1364/oe.17.009620] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Nonlinear transient absorption bleaching of intense few-cycle terahertz (THz) pulses is observed in photoexcited GaAs using opticalpump--THz-probe techniques. A simple model of the electron transport dynamics shows that the observed nonlinear response is due to THz-electric- field-induced intervalley scattering over sub-picosecond time scales as well as an increase in the intravalley scattering rate attributed to carrier heating. Furthermore, the nonlinear nature of the THz pulse transmission at high peak fields leads to a measured terahertz conductivity in the photoexcited GaAs that deviates significantly from the Drude behavior observed at low THz fields, emphasizing the need to explore nonlinear THz pulse interactions with materials in the time domain.
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Affiliation(s)
- F H Su
- Department of Physics, University of Alberta, Edmonton, Alberta, Canada
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41
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Chang TH, Wu PH, Chen SH, Chan CH, Lee CC, Chen CC, Su YK. Efficiency enhancement in GaAs solar cells using self-assembled microspheres. Opt Express 2009; 17:6519-6524. [PMID: 19365476 DOI: 10.1364/oe.17.006519] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
In this study we develop an efficient light harvesting scheme that can enhance the efficiency of GaAs solar cells using self-assembled microspheres. Based on the scattering of the microspheres and the theory of photonic crystals, the path length can be increased. In addition, the self-assembly of microspheres is one of the simplest and the fastest methods with which to build a 2D periodic structure. The experimental results are confirmed by the use of a simulation in which a finite-difference time-domain (FDTD) method is used to analyze the absorption and electric field of the 2D periodic structure. Both the results of the numerical simulations and the experimental results show an increase in the conversion power efficiency of GaAs solar cell of about 25% when 1 microm microspheres were assembled on the surface of GaAs solar cells.
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Affiliation(s)
- Te-Hung Chang
- Department of Optics and Photonics, National Central University, Chung-Li 320, Taiwan
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42
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Abstract
We report the use of Te as an n-type dopant in GaAs core-shell p-n junction nanowires for use in photovoltaic devices. Te produced significant change in the morphology of GaAs nanowires grown by the vapor-liquid-solid process in a molecular beam epitaxy system. The increase in radial growth of nanowires due to the surfactant effect of Te had a significant impact on the operating characteristics of photovoltaic devices. A decrease in solar cell efficiency occurred when the Te-doped GaAs growth duration was increased.
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Affiliation(s)
- Josef A Czaban
- Centre for Emerging Device Technologies, McMaster University, Hamilton, Ontario, Canada L8S 4L7
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43
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Perez-Bergquist A, Zhu S, Sun K, Xiang X, Zhang Y, Wang L. Embedded nanofibers induced by high-energy ion irradiation of bulk GaSb. Small 2008; 4:1119-1124. [PMID: 18651713 DOI: 10.1002/smll.200701236] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Affiliation(s)
- Alejandro Perez-Bergquist
- Department of Nuclear Engineering and Radiological Sciences, Department of Materials Science and Engineering, University of Michigan, 2355 Bonisteel Blvd., Ann Arbor, MI 48109-2104, USA
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44
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Kalliakos S, Pellegrini V, Garcia CP, Pinczuk A, Pfeiffer LN, West KW. Optical control of energy-level structure of few electrons in AlGaAs/GaAs quantum dots. Nano Lett 2008; 8:577-581. [PMID: 18186660 DOI: 10.1021/nl072904p] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Optical control of the lateral quantum confinement and number of electrons confined in nanofabricated GaAs/AlGaAs quantum dots is achieved by illumination with a weak laser beam that is absorbed in the AlGaAs barrier. Precise tuning of energy-level structure and electron population is demonstrated by monitoring the low-lying transitions of the electrons from the lowest quantum-dot energy shells by resonant inelastic light scattering. These findings open the way to the manipulation of single electrons in these quantum dots without the need of external metallic gates.
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Affiliation(s)
- Sokratis Kalliakos
- NEST INFM-CNR and Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa, Italy
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45
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Polenta L, Rossi M, Cavallini A, Calarco R, Marso M, Meijers R, Richter T, Stoica T, Lüth H. Investigation on localized states in GaN nanowires. ACS Nano 2008; 2:287-292. [PMID: 19206629 DOI: 10.1021/nn700386w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
GaN nanowires with diameters ranging between 50 and 500 nm were investigated by electrical and photoinduced current techniques to determine the influence of their size on the opto-electronic behavior of nanodevices. The conductivity, photoconductivity, and persistent photoconductivity behavior of GaN nanowires are observed to strongly depend on the wire diameter. In particular, by spectral photoconductivity measurements, three main sub-band-gap optoelectronic transitions were detected, ascribed to the localized states giving rise to the characteristic blue, green, and yellow bands of GaN. Photoconductivity with below-band-gap excitation varies orders of magnitude with the wire diameter, similarly to that observed for near-band-edge excitation. Moreover, yellow-band-related signal shows a superlinear behavior with respect to the band-edge signal, offering new information for the modeling of the carrier recombination mechanism along the nanowires. The photoconductivity results agree well with a model which takes into account a uniform distribution of the localized states inside the wire and their direct recombination with the electrons in the conduction band.
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Affiliation(s)
- L Polenta
- CNISM and Physics Department, University of Bologna, V.le Berti-Pichat 6/2, 40127 Bologna, Italy.
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46
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Abstract
We demonstrate a high-brightness compact 9 keV electron-impact microfocus x-ray source based on a liquid-gallium-jet anode. A approximately 30 W, 50 kV electron gun is focused onto the approximately 20 ms, 30 mum diameter liquid-gallium-jet anode to produce an approximately 10 microm full width at half maximum x-ray spot. The peak spectral brightness is >2 x 10(10) photons(s mm(2) mrad(2)x0.1% BW). Calculation and experiments show potential for increasing this brightness by approximately three orders of magnitude, making the source suitable for laboratory-scale x-ray crystallography and hard x-ray microscopy.
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Affiliation(s)
- M Otendal
- Biomedical and X-Ray Physics, Department of Applied Physics, Royal Institute of Technology/Albanova, SE-10691 Stockholm, Sweden.
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47
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Abstract
We investigate the physics of spontaneous emission in a photonic crystal (PhC) made of GaN rods with embedded InGaN quantum wells, formed on a thick GaN layer. Although the PhC lies on a higher-index medium, we evidence the existence of unexpected quasi-guided Bloch modes which are strongly localized in the PhC region and possess a long lifetime. These modes determine the behavior of spontaneous emission such as the emission diagram and Purcell effect, as would happen in the usual case of emission in a PhC membrane.
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Affiliation(s)
- Aurelien David
- Laboratoire Charles Fabry de l'Institut d'Optique, Campus Polytechnique, Palaiseau, France.
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48
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Chauvin N, Balet L, Alloing B, Zinoni C, Li L, Fiore A, Grenouillet L, Gilet P, Olivier N, Tchelnokov A, Terrier M, Gérard JM. Enhanced spontaneous emission from InAs/GaAs quantum dots in pillar microcavities emitting at telecom wavelengths. Opt Lett 2007; 32:2747-9. [PMID: 17873956 DOI: 10.1364/ol.32.002747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Optical properties of InAs/GaAs quantum dots in micropillar cavities emitting at 1.3 microm are studied by time-resolved microphotoluminescence. The Purcell effect is observed with an enhancement of the decay rate by a factor of two for quantum dots in resonance with the cavity mode.
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Affiliation(s)
- Nicolas Chauvin
- Ecole Polytechnique Fédérale de Lausanne (EPFL), IPEQ, Station 3, CH-1015, Lausanne, Switzerland.
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49
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Vamivakas AN, Atatüre M, Dreiser J, Yilmaz ST, Badolato A, Swan AK, Goldberg BB, Imamoglu A, Unlü MS. Strong extinction of a far-field laser beam by a single quantum dot. Nano Lett 2007; 7:2892-6. [PMID: 17691853 DOI: 10.1021/nl0717255] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Through the utilization of index-matched GaAs immersion lens techniques, we demonstrate a record extinction (12%) of a far-field focused laser beam by a single InAs/GaAs quantum dot. This contrast level enables us to report for the first time resonant laser transmission spectroscopy on a single InAs/GaAs quantum dot without the need for phase-sensitive lock-in detection.
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Affiliation(s)
- A N Vamivakas
- Department of Electrical and Computer Engineering, Boston University, Boston, Massachusetts 02215, USA
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50
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Sadowski J, Dłuzewski P, Kret S, Janik E, Lusakowska E, Kanski J, Presz A, Terki F, Charar S, Tang D. GaAs:Mn nanowires grown by molecular beam epitaxy of (Ga,Mn)as at MnAs segregation conditions. Nano Lett 2007; 7:2724-8. [PMID: 17718585 DOI: 10.1021/nl071190f] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
GaAs:Mn nanowires were obtained on GaAs(001) and GaAs(111)B substrates by molecular beam epitaxial growth of (Ga,Mn)As at conditions leading to MnAs phase separation. Their density is proportional to the density of catalyzing MnAs nanoislands, which can be controlled by the Mn flux and/or the substrate temperature. After deposition corresponding to a 200 nm thick (Ga,Mn)As layer the nanowires are around 700 nm long. Their shapes are tapered, with typical diameters around 30 nm at the base and 7 nm at the tip. The wires grow along the 111 direction, i.e., along the surface normal on GaAs(111)B and inclined on GaAs(001). In the latter case they tend to form branches. Being rooted in the ferromagnetic semiconductor (Ga,Mn)As, the nanowires combine one-dimensional properties with the magnetic properties of (Ga,Mn)As and provide natural, self-assembled structures for nanospintronics.
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Affiliation(s)
- Janusz Sadowski
- Groupe d'Etude des Semiconducteurs, Université de Montpellier 2, 34095 Montpellier, France.
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