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Chen J, Chen F, Wang X, Zhao Y, Wu Y, Cao Q, Jiang T, Li K, Li Y, Zhang J, Wu W, Che R. Room-Temperature Response Performance of Coupled Doped-Well Quantum Cascade Detectors with Array Structure. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 13:110. [PMID: 36616020 PMCID: PMC9824534 DOI: 10.3390/nano13010110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Revised: 12/23/2022] [Accepted: 12/24/2022] [Indexed: 06/17/2023]
Abstract
Energy level interaction and electron concentration are crucial aspects that affect the response performance of quantum cascade detectors (QCDs). In this work, two different-structured array QCDs are prepared, and the detectivity reaches 109 cm·Hz1/2/W at room temperature. The overlap integral (OI) and oscillator strength (OS) between different energy levels under a series of applied biases are fitted and reveal the influence of energy level interaction on the response performance. The redistribution of electrons in the cascade structure at room temperatures is established. The coupled doped-well structure shows a higher electron concentration at room temperature, which represents a high absorption efficiency in the active region. Even better responsivity and detectivity are exhibited in the coupled doped-well QCD. These results offer a novel strategy to understand the mechanisms that affect response performance and expand the application range of QCDs for long-wave infrared (LWIR) detection.
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Affiliation(s)
- Jie Chen
- Laboratory of Advanced Materials, Shanghai Key Lab of Molecular Catalysis and Innovative Materials, Academy for Engineering & Technology, Fudan University, Shanghai 200438, China
- Laser Fusion Research Center, China Academy of Engineering Physics, Mianyang 621900, China
| | - Fengwei Chen
- Laser Fusion Research Center, China Academy of Engineering Physics, Mianyang 621900, China
| | - Xuemin Wang
- Laser Fusion Research Center, China Academy of Engineering Physics, Mianyang 621900, China
| | - Yunhao Zhao
- Laboratory of Advanced Materials, Shanghai Key Lab of Molecular Catalysis and Innovative Materials, Academy for Engineering & Technology, Fudan University, Shanghai 200438, China
| | - Yuyang Wu
- Laboratory of Advanced Materials, Shanghai Key Lab of Molecular Catalysis and Innovative Materials, Academy for Engineering & Technology, Fudan University, Shanghai 200438, China
| | - Qingchen Cao
- Laboratory of Advanced Materials, Shanghai Key Lab of Molecular Catalysis and Innovative Materials, Academy for Engineering & Technology, Fudan University, Shanghai 200438, China
| | - Tao Jiang
- Laser Fusion Research Center, China Academy of Engineering Physics, Mianyang 621900, China
| | - Keyu Li
- Laser Fusion Research Center, China Academy of Engineering Physics, Mianyang 621900, China
| | - Yang Li
- Laser Fusion Research Center, China Academy of Engineering Physics, Mianyang 621900, China
| | | | - Weidong Wu
- Laser Fusion Research Center, China Academy of Engineering Physics, Mianyang 621900, China
| | - Renchao Che
- Laboratory of Advanced Materials, Shanghai Key Lab of Molecular Catalysis and Innovative Materials, Academy for Engineering & Technology, Fudan University, Shanghai 200438, China
- Zhejiang Laboratory, Hangzhou 311100, China
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2
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Ren L, Lombez L, Robert C, Beret D, Lagarde D, Urbaszek B, Renucci P, Taniguchi T, Watanabe K, Crooker SA, Marie X. Optical Detection of Long Electron Spin Transport Lengths in a Monolayer Semiconductor. PHYSICAL REVIEW LETTERS 2022; 129:027402. [PMID: 35867459 DOI: 10.1103/physrevlett.129.027402] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 05/18/2022] [Indexed: 06/15/2023]
Abstract
Using a spatially resolved optical pump-probe experiment, we measure the lateral transport of spin-valley polarized electrons over very long distances (tens of micrometers) in a single WSe_{2} monolayer. By locally pumping the Fermi sea of 2D electrons to a high degree of spin-valley polarization (up to 75%) using circularly polarized light, the lateral diffusion of the electron polarization can be mapped out via the photoluminescence induced by a spatially separated and linearly polarized probe laser. Up to 25% spin-valley polarization is observed at pump-probe separations up to 20 μm. Characteristic spin-valley diffusion lengths of 18±3 μm are revealed at low temperatures. The dependence on temperature, pump helicity, pump intensity, and electron density highlight the key roles played by spin relaxation time and pumping efficiency on polarized electron transport in monolayer semiconductors possessing spin-valley locking.
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Affiliation(s)
- L Ren
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, 31077 Toulouse, France
| | - L Lombez
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, 31077 Toulouse, France
| | - C Robert
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, 31077 Toulouse, France
| | - D Beret
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, 31077 Toulouse, France
| | - D Lagarde
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, 31077 Toulouse, France
| | - B Urbaszek
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, 31077 Toulouse, France
| | - P Renucci
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, 31077 Toulouse, France
| | - T Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-00044, Japan
| | - K Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-00044, Japan
| | - S A Crooker
- National High Magnetic Field Laboratory, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - X Marie
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, 31077 Toulouse, France
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Smolinsky EZB, Neubauer A, Kumar A, Yochelis S, Capua E, Carmieli R, Paltiel Y, Naaman R, Michaeli K. Electric Field-Controlled Magnetization in GaAs/AlGaAs Heterostructures-Chiral Organic Molecules Hybrids. J Phys Chem Lett 2019; 10:1139-1145. [PMID: 30785758 DOI: 10.1021/acs.jpclett.9b00092] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
We study GaAs/AlGaAs devices hosting a two-dimensional electron gas and coated with a monolayer of chiral organic molecules. We observe clear signatures of room-temperature magnetism, which is induced in these systems by applying a gate voltage. We explain this phenomenon as a consequence of the spin-polarized charges that are injected into the semiconductor through the chiral molecules. The orientation of the magnetic moment can be manipulated by low gate voltages, with a switching rate in the megahertz range. Thus, our devices implement an efficient, electric field-controlled magnetization, which has long been desired for their technical prospects.
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Affiliation(s)
| | - Avner Neubauer
- Department of Applied Physics and Center for Nano Science and Nanotechnology , The Hebrew University , Jerusalem 91904 , Israel
| | | | - Shira Yochelis
- Department of Applied Physics and Center for Nano Science and Nanotechnology , The Hebrew University , Jerusalem 91904 , Israel
| | | | | | - Yossi Paltiel
- Department of Applied Physics and Center for Nano Science and Nanotechnology , The Hebrew University , Jerusalem 91904 , Israel
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4
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Strong confinement-induced engineering of the g factor and lifetime of conduction electron spins in Ge quantum wells. Nat Commun 2016; 7:13886. [PMID: 28000670 PMCID: PMC5187588 DOI: 10.1038/ncomms13886] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 11/09/2016] [Indexed: 11/08/2022] Open
Abstract
Control of electron spin coherence via external fields is fundamental in spintronics. Its implementation demands a host material that accommodates the desirable but contrasting requirements of spin robustness against relaxation mechanisms and sizeable coupling between spin and orbital motion of the carriers. Here, we focus on Ge, which is a prominent candidate for shuttling spin quantum bits into the mainstream Si electronics. So far, however, the intrinsic spin-dependent phenomena of free electrons in conventional Ge/Si heterojunctions have proved to be elusive because of epitaxy constraints and an unfavourable band alignment. We overcome these fundamental limitations by investigating a two-dimensional electron gas in quantum wells of pure Ge grown on Si. These epitaxial systems demonstrate exceptionally long spin lifetimes. In particular, by fine-tuning quantum confinement we demonstrate that the electron Landé g factor can be engineered in our CMOS-compatible architecture over a range previously inaccessible for Si spintronics.
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Nádvorník L, Němec P, Janda T, Olejník K, Novák V, Skoromets V, Němec H, Kužel P, Trojánek F, Jungwirth T, Wunderlich J. Long-range and high-speed electronic spin-transport at a GaAs/AlGaAs semiconductor interface. Sci Rep 2016; 6:22901. [PMID: 26980667 PMCID: PMC4793250 DOI: 10.1038/srep22901] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 02/24/2016] [Indexed: 11/09/2022] Open
Abstract
Spin-valves or spin-transistors in magnetic memories and logic elements are examples of structures whose functionality depends crucially on the length and time-scales at which spin-information is transferred through the device. In our work we employ spatially resolved optical pump-and-probe technique to investigate these fundamental spin-transport parameters in a model semiconductor system. We demonstrate that in an undoped GaAs/AlGaAs layer, spins are detected at distances reaching more than ten microns at times as short as nanoseconds. We have achieved this unprecedented combination of long-range and high-speed electronic spin-transport by simultaneously suppressing mechanisms that limit the spin life-time and the mobility of carriers. By exploring a series of structures we demonstrate that the GaAs/AlGaAs interface can provide superior spin-transport characteristics whether deposited directly on the substrate or embedded in complex semiconductor heterostructures. We confirm our conclusions by complementing the optical experiments with dc and terahertz photo-conductivity measurements.
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Affiliation(s)
- L Nádvorník
- Institute of Physics ASCR, v.v.i., Cukrovarnická 10, 16253 Praha 6, Czech Republic.,Faculty of Mathematics and Physics, Charles University, Ke Karlovu 3, 12116 Praha 2, Czech Republic
| | - P Němec
- Faculty of Mathematics and Physics, Charles University, Ke Karlovu 3, 12116 Praha 2, Czech Republic
| | - T Janda
- Institute of Physics ASCR, v.v.i., Cukrovarnická 10, 16253 Praha 6, Czech Republic.,Faculty of Mathematics and Physics, Charles University, Ke Karlovu 3, 12116 Praha 2, Czech Republic
| | - K Olejník
- Institute of Physics ASCR, v.v.i., Cukrovarnická 10, 16253 Praha 6, Czech Republic
| | - V Novák
- Institute of Physics ASCR, v.v.i., Cukrovarnická 10, 16253 Praha 6, Czech Republic
| | - V Skoromets
- Institute of Physics ASCR, v.v.i., Na Slovance 2, 18221 Praha 8, Czech Republic
| | - H Němec
- Institute of Physics ASCR, v.v.i., Na Slovance 2, 18221 Praha 8, Czech Republic
| | - P Kužel
- Institute of Physics ASCR, v.v.i., Na Slovance 2, 18221 Praha 8, Czech Republic
| | - F Trojánek
- Faculty of Mathematics and Physics, Charles University, Ke Karlovu 3, 12116 Praha 2, Czech Republic
| | - T Jungwirth
- Institute of Physics ASCR, v.v.i., Cukrovarnická 10, 16253 Praha 6, Czech Republic.,School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, UK
| | - J Wunderlich
- Institute of Physics ASCR, v.v.i., Cukrovarnická 10, 16253 Praha 6, Czech Republic.,Hitachi Cambridge Laboratory, J. J. Thomson Avenue, CB3 0HE Cambridge, UK
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Henn T, Kiessling T, Ossau W, Molenkamp LW, Biermann K, Santos PV. Ultrafast supercontinuum fiber-laser based pump-probe scanning magneto-optical Kerr effect microscope for the investigation of electron spin dynamics in semiconductors at cryogenic temperatures with picosecond time and micrometer spatial resolution. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2013; 84:123903. [PMID: 24387442 DOI: 10.1063/1.4842276] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
We describe a two-color pump-probe scanning magneto-optical Kerr effect microscope which we have developed to investigate electron spin phenomena in semiconductors at cryogenic temperatures with picosecond time and micrometer spatial resolution. The key innovation of our microscope is the usage of an ultrafast "white light" supercontinuum fiber-laser source which provides access to the whole visible and near-infrared spectral range. Our Kerr microscope allows for the independent selection of the excitation and detection energy while avoiding the necessity to synchronize the pulse trains of two separate picosecond laser systems. The ability to independently tune the pump and probe wavelength enables the investigation of the influence of excitation energy on the optically induced electron spin dynamics in semiconductors. We demonstrate picosecond real-space imaging of the diffusive expansion of optically excited electron spin packets in a (110) GaAs quantum well sample to illustrate the capabilities of the instrument.
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Affiliation(s)
- T Henn
- Physikalisches Institut (EP3), Universität Würzburg, 97074 Würzburg, Germany
| | - T Kiessling
- Physikalisches Institut (EP3), Universität Würzburg, 97074 Würzburg, Germany
| | - W Ossau
- Physikalisches Institut (EP3), Universität Würzburg, 97074 Würzburg, Germany
| | - L W Molenkamp
- Physikalisches Institut (EP3), Universität Würzburg, 97074 Würzburg, Germany
| | - K Biermann
- Paul-Drude-Institut für Festkörperelektronik, 10117 Berlin, Germany
| | - P V Santos
- Paul-Drude-Institut für Festkörperelektronik, 10117 Berlin, Germany
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Balocchi A, Duong QH, Renucci P, Liu BL, Fontaine C, Amand T, Lagarde D, Marie X. Full electrical control of the electron spin relaxation in GaAs quantum wells. PHYSICAL REVIEW LETTERS 2011; 107:136604. [PMID: 22026883 DOI: 10.1103/physrevlett.107.136604] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Indexed: 05/31/2023]
Abstract
The electron spin dynamics in (111)-oriented GaAs/AlGaAs quantum wells is studied by time-resolved photoluminescence spectroscopy. By applying an external electric field of 50 kV/cm a two-order of magnitude increase of the spin relaxation time can be observed reaching values larger than 30 ns; this is a consequence of the electric field tuning of the spin-orbit conduction band splitting which can almost vanish when the Rashba term compensates exactly the Dresselhaus one. The measurements under a transverse magnetic field demonstrate that the electron spin relaxation time for the three space directions can be tuned simultaneously with the applied electric field.
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Affiliation(s)
- A Balocchi
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, France
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