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Schmiedeke P, Döblinger M, Meinhold-Heerlein MA, Doganlar C, Finley JJ, Koblmüller G. Sb-saturated high-temperature growth of extended, self-catalyzed GaAsSb nanowires on silicon with high quality. NANOTECHNOLOGY 2023; 35:055601. [PMID: 37879325 DOI: 10.1088/1361-6528/ad06ce] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 10/25/2023] [Indexed: 10/27/2023]
Abstract
Ternary GaAsSb nanowires (NW) are key materials for integrated high-speed photonic applications on silicon (Si), where homogeneous, high aspect-ratio dimensions and high-quality properties for controlled absorption, mode confinement and waveguiding are much desired. Here, we demonstrate a unique high-temperature (high-T >650 °C) molecular beam epitaxial (MBE) approach to realize self-catalyzed GaAsSb NWs site-selectively on Si with high aspect-ratio and non-tapered morphologies under antimony (Sb)-saturated conditions. While hitherto reported low-moderate temperature growth processes result in early growth termination and inhomogeneous morphologies, the non-tapered nature of NWs under high-T growth is independent of the supply rates of relevant growth species. Analysis of dedicated Ga-flux and growth time series, allows us to pinpoint the microscopic mechanisms responsible for the elimination of tapering, namely concurrent vapor-solid, step-flow growth along NW side-facets enabled by enhanced Ga diffusion under the high-T growth. Performing growth in an Sb-saturated regime, leads to high Sb-content in VLS-GaAsSb NW close to 30% that is independent of Ga-flux. This independence enables multi-step growth via sequentially increased Ga-flux to realize uniform and very long (>7μm) GaAsSb NWs. The excellent properties of these NWs are confirmed by a completely phase-pure, twin-free zincblende (ZB) crystal structure, a homogeneous Sb-content along the VLS-GaAsSb NW growth axis, along with remarkably narrow, single-peak low-temperature photoluminescence linewidth (<15 meV) at wavelengths of ∼1100-1200 nm.
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Affiliation(s)
- P Schmiedeke
- Walter Schottky Institute and Physics Department, TUM School of Natural Sciences, Technical University of Munich, Garching, Germany
| | - M Döblinger
- Department of Chemistry, Ludwig-Maximilians-University Munich, Munich, Germany
| | - M A Meinhold-Heerlein
- Walter Schottky Institute and Physics Department, TUM School of Natural Sciences, Technical University of Munich, Garching, Germany
| | - C Doganlar
- Walter Schottky Institute and Physics Department, TUM School of Natural Sciences, Technical University of Munich, Garching, Germany
| | - J J Finley
- Walter Schottky Institute and Physics Department, TUM School of Natural Sciences, Technical University of Munich, Garching, Germany
| | - G Koblmüller
- Walter Schottky Institute and Physics Department, TUM School of Natural Sciences, Technical University of Munich, Garching, Germany
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2
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Leshchenko ED, Dubrovskii VG. An Overview of Modeling Approaches for Compositional Control in III-V Ternary Nanowires. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:nano13101659. [PMID: 37242075 DOI: 10.3390/nano13101659] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 05/11/2023] [Accepted: 05/15/2023] [Indexed: 05/28/2023]
Abstract
Modeling of the growth process is required for the synthesis of III-V ternary nanowires with controllable composition. Consequently, new theoretical approaches for the description of epitaxial growth and the related chemical composition of III-V ternary nanowires based on group III or group V intermix were recently developed. In this review, we present and discuss existing modeling strategies for the stationary compositions of III-V ternary nanowires and try to systematize and link them in a general perspective. In particular, we divide the existing approaches into models that focus on the liquid-solid incorporation mechanisms in vapor-liquid-solid nanowires (equilibrium, nucleation-limited, and kinetic models treating the growth of solid from liquid) and models that provide the vapor-solid distributions (empirical, transport-limited, reaction-limited, and kinetic models treating the growth of solid from vapor). We describe the basic ideas underlying the existing models and analyze the similarities and differences between them, as well as the limitations and key factors influencing the stationary compositions of III-V nanowires versus the growth method. Overall, this review provides a basis for choosing a modeling approach that is most appropriate for a particular material system and epitaxy technique and that underlines the achieved level of the compositional modeling of III-V ternary nanowires and the remaining gaps that require further studies.
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Affiliation(s)
- Egor D Leshchenko
- Faculty of Physics, St. Petersburg State University, Universitetskaya Emb. 13B, 199034 St. Petersburg, Russia
| | - Vladimir G Dubrovskii
- Faculty of Physics, St. Petersburg State University, Universitetskaya Emb. 13B, 199034 St. Petersburg, Russia
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3
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Devkota S, Kuchoor H, Dawkins K, Pokharel R, Parakh M, Li J, Iyer S. Heterostructure axial GaAsSb ensemble near-infrared p-i-n based axial configured nanowire photodetectors. NANOTECHNOLOGY 2023; 34:265204. [PMID: 36893449 DOI: 10.1088/1361-6528/acc2c6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 03/09/2023] [Indexed: 06/18/2023]
Abstract
In this work, we present a systematic design of growth experiments and subsequent characterization of self-catalyzed molecular beam epitaxially grown GaAsSb heterostructure axial p-i-n nanowires (NWs) on p-Si <111> for the ensemble photodetector (PD) application in the near-infrared region. Diverse growth methods have been explored to gain a better insight into mitigating several growth challenges by systematically studying their impact on the NW electrical and optical properties to realize a high-quality p-i-n heterostructure. The successful growth approaches are Te-dopant compensation to suppress the p-type nature of intrinsic GaAsSb segment, growth interruption for strain relaxation at the interface, decreased substrate temperature to enhance supersaturation and minimize the reservoir effect, higher bandgap compositions of the n-segment of the heterostructure relative to the intrinsic region for boosting the absorption, and the high-temperature ultra-high vacuumin situannealing to reduce the parasitic radial overgrowth. The efficacy of these methods is supported by enhanced photoluminescence (PL) emission, suppressed dark current in the heterostructure p-i-n NWs accompanied by increased rectification ratio, photosensitivity, and a reduced low-frequency noise level. The PD fabricated utilizing the optimized GaAsSb axial p-i-n NWs exhibited the longer wavelength cutoff at ∼1.1μm with a significantly higher responsivity of ∼120 A W-1(@-3 V bias) and a detectivity of 1.1 × 1013Jones operating at room temperature. Frequency and the bias independent capacitance in the pico-Farad (pF) range and substantially lower noise level at the reverse biased condition, show the prospects of p-i-n GaAsSb NWs PD for high-speed optoelectronic applications.
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Affiliation(s)
- Shisir Devkota
- Department of Nanoengineering, Joint School of Nanoscience and Nanoengineering, North Carolina A&T State University, Greensboro, NC 27401, United States of America
| | - Hirandeep Kuchoor
- Department of Nanoengineering, Joint School of Nanoscience and Nanoengineering, North Carolina A&T State University, Greensboro, NC 27401, United States of America
| | - Kendall Dawkins
- Department of Nanoengineering, Joint School of Nanoscience and Nanoengineering, North Carolina A&T State University, Greensboro, NC 27401, United States of America
| | - Rabin Pokharel
- Department of Nanoengineering, Joint School of Nanoscience and Nanoengineering, North Carolina A&T State University, Greensboro, NC 27401, United States of America
| | - Mehul Parakh
- Department of Nanoengineering, Joint School of Nanoscience and Nanoengineering, North Carolina A&T State University, Greensboro, NC 27401, United States of America
| | - Jia Li
- Department of Nanoengineering, Joint School of Nanoscience and Nanoengineering, North Carolina A&T State University, Greensboro, NC 27401, United States of America
| | - Shanthi Iyer
- Department of Nanoengineering, Joint School of Nanoscience and Nanoengineering, North Carolina A&T State University, Greensboro, NC 27401, United States of America
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4
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Yuan L, Pokharel R, Devkota S, Kuchoor H, Dawkins K, Lee MC, Huang Y, Yarotski D, Iyer S, Prasankumar RP. Revealing charge carrier dynamics and transport in Te-doped GaAsSb and GaAsSbN nanowires by correlating ultrafast terahertz spectroscopy and optoelectronic characterization. NANOTECHNOLOGY 2022; 33:425702. [PMID: 35772308 DOI: 10.1088/1361-6528/ac7d61] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 06/30/2022] [Indexed: 06/15/2023]
Abstract
Recent advances in the growth of III-V semiconductor nanowires (NWs) hold great promise for nanoscale optoelectronic device applications. It is established that a small amount of nitrogen (N) incorporation in III-V semiconductor NWs can effectively red-shift their wavelength of operation and tailor their electronic properties for specific applications. However, understanding the impact of N incorporation on non-equilibrium charge carrier dynamics and transport in semiconducting NWs is critical in achieving efficient semiconducting NW devices. In this work, ultrafast optical pump-terahertz probe spectroscopy has been used to study non-equilibrium carrier dynamics and transport in Te-doped GaAsSb and dilute nitride GaAsSbN NWs, with the goal of correlating these results with electrical characterization of their equilibrium photo-response under bias and low-frequency noise characteristics. Nitrogen incorporation in GaAsSb NWs led to a significant increase in the carrier scattering rate, resulting in a severe reduction in carrier mobility. Carrier recombination lifetimes of 33 ± 1 picoseconds (ps) and 147 ± 3 ps in GaAsSbN and GaAsSb NWs, respectively, were measured. The reduction in the carrier lifetime and photoinduced optical conductivities are due to the presence of N-induced defects, leading to deterioration in the electrical and optical characteristics of dilute nitride NWs relative to the non-nitride NWs. Finally, we observed a very fast rise time of ∼2 ps for both NW materials, directly impacting their potential use as high-speed photodetectors.
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Affiliation(s)
- Long Yuan
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM 87545, United States of America
| | - Rabin Pokharel
- Nanoengineering Department, Joint School of Nanoscience and Nanoengineering, North Carolina A&T University, Greensboro, NC 27401, United States of America
| | - Shisir Devkota
- Nanoengineering Department, Joint School of Nanoscience and Nanoengineering, North Carolina A&T University, Greensboro, NC 27401, United States of America
| | - Hirandeep Kuchoor
- Nanoengineering Department, Joint School of Nanoscience and Nanoengineering, North Carolina A&T University, Greensboro, NC 27401, United States of America
| | - Kendall Dawkins
- Nanoengineering Department, Joint School of Nanoscience and Nanoengineering, North Carolina A&T University, Greensboro, NC 27401, United States of America
| | - Min-Cheol Lee
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM 87545, United States of America
| | - Yue Huang
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM 87545, United States of America
| | - Dzmitry Yarotski
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM 87545, United States of America
| | - Shanthi Iyer
- Nanoengineering Department, Joint School of Nanoscience and Nanoengineering, North Carolina A&T University, Greensboro, NC 27401, United States of America
| | - Rohit P Prasankumar
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM 87545, United States of America
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5
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Parakh M, Ramaswamy P, Devkota S, Kuchoor H, Dawkins K, Iyer S. Passivation efficacy study of Al 2O 3dielectric on self-catalyzed molecular beam epitaxially grown GaAs 1-xSb xnanowires. NANOTECHNOLOGY 2022; 33:315602. [PMID: 35468592 DOI: 10.1088/1361-6528/ac69f8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Accepted: 04/22/2022] [Indexed: 06/14/2023]
Abstract
This work evaluates the passivation efficacy of thermal atomic layer deposited (ALD) Al2O3dielectric layer on self-catalyzed GaAs1-xSbxnanowires (NWs) grown using molecular beam epitaxy. A detailed assessment of surface chemical composition and optical properties of Al2O3passivated NWs with and without prior sulfur treatment were studied and compared to as-grown samples using x-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and low-temperature photoluminescence (PL) spectroscopy. The XPS measurements reveal that prior sulfur treatment followed by Al2O3ALD deposition abates III-V native oxides from the NW surface. However, the degradation in 4K-PL intensity by an order of magnitude observed for NWs with Al2O3shell layer compared to the as-grown NWs, irrespective of prior sulfur treatment, suggests the formation of defect states at the NW/dielectric interface contributing to non-radiative recombination centers. This is corroborated by the Raman spectral broadening of LO and TO Raman modes, increased background scattering, and redshift observed for Al2O3deposited NWs relative to the as-grown. Thus, our work seems to indicate the unsuitability of ALD deposited Al2O3as a passivation layer for GaAsSb NWs.
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Affiliation(s)
- Mehul Parakh
- Nanoengineering, Joint School of Nanoscience and Nanoengineering, North Carolina A&T State University, Greensboro NC, 27401, United States of Americ a
| | - Priyanka Ramaswamy
- Department of Electrical and Computer Engineering, North Carolina A&T State University, Greensboro NC, 27411, United States of America
| | - Shisir Devkota
- Nanoengineering, Joint School of Nanoscience and Nanoengineering, North Carolina A&T State University, Greensboro NC, 27401, United States of Americ a
| | - Hirandeep Kuchoor
- Nanoengineering, Joint School of Nanoscience and Nanoengineering, North Carolina A&T State University, Greensboro NC, 27401, United States of Americ a
| | - Kendall Dawkins
- Nanoengineering, Joint School of Nanoscience and Nanoengineering, North Carolina A&T State University, Greensboro NC, 27401, United States of Americ a
| | - Shanthi Iyer
- Nanoengineering, Joint School of Nanoscience and Nanoengineering, North Carolina A&T State University, Greensboro NC, 27401, United States of Americ a
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6
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Optical Investigation of p-GaAs/i-GaN0.38yAs1-1.38ySby/n-GaAs Quantum Wells Emitters. JOURNAL OF NANOTECHNOLOGY 2022. [DOI: 10.1155/2022/7971119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We have studied the 1.55 μm optical properties of p-GaAs/i-GaN0.38yAs1-1.38ySby/n-GaAs quantum wells using a self-consistent calculation combined with the anticrossing model. We have found that the increase of injected carriers’ density induces the increase of optical gain and radiative current density. The rise of doping density causes a blue shift of the fundamental transition energy accompanied with significant increase of optical gain. The quantum-confined Stark effect on radiative current density is also studied. The variation of radiative current as function of well width and Sb composition is also examined. In order to operate the emission wavelength at the optical fiber telecommunication domain, we have adjusted the well parameters of p-GaAs/i-GaN0.38yAs1-1.38ySby/n-GaAs.
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7
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Ruhstorfer D, Lang A, Matich S, Döblinger M, Riedl H, Finley JJ, Koblmüller G. Growth dynamics and compositional structure in periodic InAsSb nanowire arrays on Si (111) grown by selective area molecular beam epitaxy. NANOTECHNOLOGY 2021; 32:135604. [PMID: 33238260 DOI: 10.1088/1361-6528/abcdca] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We report a comprehensive study of the growth dynamics in highly periodic, composition tunable InAsSb nanowire (NW) arrays using catalyst-free selective area molecular beam epitaxy. Employing periodically patterned SiO2-masks on Si (111) with various mask opening sizes (20-150 nm) and pitches (0.25-2 μm), high NW yield of >90% (irrespective of the InAsSb alloy composition) is realized by the creation of an As-terminated 1 × 1-Si(111) surface prior to NW nucleation. While the NW aspect ratio decreases continually with increasing Sb content (x Sb from 0% to 30%), we find a remarkable dependence of the aspect ratio on the mask opening size yielding up to ∼8-fold increase for openings decreasing from 150 to 20 nm. The effects of the interwire separation (pitch) on the NW aspect ratio are strongest for pure InAs NWs and gradually vanish for increasing Sb content, suggesting that growth of InAsSb NW arrays is governed by an In surface diffusion limited regime even for the smallest investigated pitches. Compositional analysis using high-resolution x-ray diffraction reveals a substantial impact of the pitch on the alloy composition in homogeneous InAsSb NW arrays, leading to much larger x Sb as the pitch increases due to decreasing competition for Sb adatoms. Scanning transmission electron microscopy and associated energy-dispersive x-ray spectroscopy performed on the cross-sections of individual NWs reveal an interesting growth-axis dependent core-shell like structure with a discontinuous few-nm thick Sb-deficient coaxial boundary layer and six Sb-deficient corner bands. Further analysis evidences the presence of a nanoscale facet at the truncation of the (111)B growth front and {1-10} sidewall surfaces that is found responsible for the formation of the characteristic core-shell structure.
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Affiliation(s)
- Daniel Ruhstorfer
- Walter Schottky Institute and Physics Department, Technical University of Munich, Garching, Germany
| | - Armin Lang
- Walter Schottky Institute and Physics Department, Technical University of Munich, Garching, Germany
| | - Sonja Matich
- Walter Schottky Institute and Physics Department, Technical University of Munich, Garching, Germany
| | - Markus Döblinger
- Department of Chemistry, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Hubert Riedl
- Walter Schottky Institute and Physics Department, Technical University of Munich, Garching, Germany
| | - Jonathan J Finley
- Walter Schottky Institute and Physics Department, Technical University of Munich, Garching, Germany
| | - Gregor Koblmüller
- Walter Schottky Institute and Physics Department, Technical University of Munich, Garching, Germany
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8
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Johnson S, Pokharel R, Lowe M, Kuchoor H, Nalamati S, Davis K, Rathnayake H, Iyer S. Study of patterned GaAsSbN nanowires using sigmoidal model. Sci Rep 2021; 11:4651. [PMID: 33633245 PMCID: PMC7907112 DOI: 10.1038/s41598-021-83973-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 02/05/2021] [Indexed: 01/31/2023] Open
Abstract
This study presents the first report on patterned nanowires (NWs) of dilute nitride GaAsSbN on p-Si (111) substrates by self-catalyzed plasma-assisted molecular beam epitaxy. Patterned NW array with GaAsSbN of Sb composition of 3% as a stem provided the best yield of vertical NWs. Large bandgap tuning of ~ 75 meV, as ascertained from 4 K photoluminescence (PL), over a pitch length variation of 200-1200 nm has been demonstrated. Pitch-dependent axial and radial growth rates show a logistic sigmoidal growth trend different from those commonly observed in other patterned non-nitride III-V NWs. The sigmoidal fitting provides further insight into the PL spectral shift arising from differences in Sb and N incorporation from pitch induced variation in secondary fluxes. Results indicate that sigmoidal fitting can be a potent tool for designing patterned NW arrays of optimal pitch length for dilute nitrides and other highly mismatched alloys and heterostructures.
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Affiliation(s)
- Sean Johnson
- grid.261037.10000 0001 0287 4439Department of Electrical and Computer Engineering, North Carolina A&T State University, Greensboro, NC 27411 USA
| | - Rabin Pokharel
- grid.261037.10000 0001 0287 4439Nanoengineering, Joint School of Nanoscience and Nanoengineering, North Carolina A&T State University, Greensboro, NC 27401 USA
| | - Michael Lowe
- grid.261037.10000 0001 0287 4439Department of Electrical and Computer Engineering, North Carolina A&T State University, Greensboro, NC 27411 USA
| | - Hirandeep Kuchoor
- grid.261037.10000 0001 0287 4439Nanoengineering, Joint School of Nanoscience and Nanoengineering, North Carolina A&T State University, Greensboro, NC 27401 USA
| | - Surya Nalamati
- grid.261037.10000 0001 0287 4439Department of Electrical and Computer Engineering, North Carolina A&T State University, Greensboro, NC 27411 USA
| | - Klinton Davis
- grid.266860.c0000 0001 0671 255XNanoscience, Joint School of Nanoscience and Nanoengineering, University of North Carolina At Greensboro, Greensboro, NC 27401 USA
| | - Hemali Rathnayake
- grid.266860.c0000 0001 0671 255XNanoscience, Joint School of Nanoscience and Nanoengineering, University of North Carolina At Greensboro, Greensboro, NC 27401 USA
| | - Shanthi Iyer
- grid.261037.10000 0001 0287 4439Nanoengineering, Joint School of Nanoscience and Nanoengineering, North Carolina A&T State University, Greensboro, NC 27401 USA
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9
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Ghasemi M, Leshchenko ED, Johansson J. Assembling your nanowire: an overview of composition tuning in ternary III-V nanowires. NANOTECHNOLOGY 2021; 32:072001. [PMID: 33091889 DOI: 10.1088/1361-6528/abc3e2] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The ability to grow defect-free nanowires in lattice-mismatched material systems and to design their properties has made them ideal candidates for applications in fields as diverse as nanophotonics, nanoelectronics and medicine. After studying nanostructures consisting of elemental and binary compound semiconductors, scientists turned their attention to more complex systems-ternary nanowires. Composition control is key in these nanostructures since it enables bandgap engineering. The use of different combinations of compounds and different growth methods has resulted in numerous investigations. The aim of this review is to present a survey of the material systems studied to date, and to give a brief overview of the issues tackled and the progress achieved in nanowire composition tuning. We focus on ternary III x III1-x V nanowires (AlGaAs, AlGaP, AlInP, InGaAs, GaInP and InGaSb) and IIIV x V1-x nanowires (InAsP, InAsSb, InPSb, GaAsP, GaAsSb and GaSbP).
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Affiliation(s)
| | - Egor D Leshchenko
- Solid State Physics and NanoLund, Lund University, P O Box 118, SE-221 00 Lund, Sweden
| | - Jonas Johansson
- Solid State Physics and NanoLund, Lund University, P O Box 118, SE-221 00 Lund, Sweden
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10
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Leshchenko ED, Johansson J. Role of Thermodynamics and Kinetics in the Composition of Ternary III-V Nanowires. NANOMATERIALS 2020; 10:nano10122553. [PMID: 33353245 PMCID: PMC7766982 DOI: 10.3390/nano10122553] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 12/15/2020] [Accepted: 12/15/2020] [Indexed: 11/22/2022]
Abstract
We explain the composition of ternary nanowires nucleating from a quaternary liquid melt. The model we derive describes the evolution of the solid composition from the nucleated-limited composition to the kinetic one. The effect of the growth temperature, group V concentration and Au/III concentration ratio on the solid-liquid dependence is studied. It has been shown that the solid composition increases with increasing temperature and Au concentration in the droplet at the fixed In/Ga concentration ratio. The model does not depend on the site of nucleation and the geometry of monolayer growth and is applicable for nucleation and growth on a facet with finite radius. The case of a steady-state (or final) solid composition is considered and discussed separately. While the nucleation-limited liquid-solid composition dependence contains the miscibility gap at relevant temperatures for growth of InxGa1−xAs NWs, the miscibility gap may be suppressed completely in the steady-state growth regime at high supersaturation. The theoretical results are compared with available experimental data via the combination of the here described solid-liquid and a simple kinetic liquid-vapor model.
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11
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Devkota S, Parakh M, Johnson S, Ramaswamy P, Lowe M, Penn A, Reynolds L, Iyer S. A study of n-doping in self-catalyzed GaAsSb nanowires using GaTe dopant source and ensemble nanowire near-infrared photodetector. NANOTECHNOLOGY 2020; 31:505203. [PMID: 33021209 DOI: 10.1088/1361-6528/abb506] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
This work reports a comprehensive investigation of the effect of gallium telluride (GaTe) cell temperature variation (TGaTe) on the morphological, optical, and electrical properties of doped-GaAsSb nanowires (NWs) grown by Ga-assisted molecular beam epitaxy (MBE). These studies led to an optimum doping temperature of 550 °C for the growth of tellurium (Te)-doped GaAsSb NWs with the best optoelectronic and structural properties. Te incorporation resulted in a decrease in the aspect ratio of the NWs causing an increase in the Raman longitudinal optical/transverse optical vibrational mode intensity ratio, large photoluminescence emission with an exponential decay tail on the high energy side, promoting tunnel-assisted current conduction in ensemble NWs and significant photocurrent enhancement in the single nanowire. A Schottky barrier photodetector (PD) using Te-doped ensemble NWs with broad spectral range and a longer wavelength cutoff at ∼1.2 µm was demonstrated. These PDs exhibited responsivity in the range of 580-620 A W-1 and detectivity of 1.2-3.8 × 1012 Jones. The doped GaAsSb NWs have the potential for further improvement, paving the path for high-performance near-infrared (NIR) photodetection applications.
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Affiliation(s)
- Shisir Devkota
- Nanoengineering, Joint School of Nanoscience and Nanoengineering, North Carolina A&T State University, Greensboro, NC 27401, United States of America
| | - Mehul Parakh
- Nanoengineering, Joint School of Nanoscience and Nanoengineering, North Carolina A&T State University, Greensboro, NC 27401, United States of America
| | - Sean Johnson
- Department of Electrical and Computer Engineering, North Carolina A&T State University, Greensboro, NC 27411, United States of America
| | - Priyanka Ramaswamy
- Department of Electrical and Computer Engineering, North Carolina A&T State University, Greensboro, NC 27411, United States of America
| | - Michael Lowe
- Department of Electrical and Computer Engineering, North Carolina A&T State University, Greensboro, NC 27411, United States of America
| | - Aubrey Penn
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27695, United States of America
- Analytical Instrumentation Facility, North Carolina State University, Raleigh, NC 27695, United States of America
| | - Lew Reynolds
- Analytical Instrumentation Facility, North Carolina State University, Raleigh, NC 27695, United States of America
| | - Shanthi Iyer
- Nanoengineering, Joint School of Nanoscience and Nanoengineering, North Carolina A&T State University, Greensboro, NC 27401, United States of America
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12
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Recent Progress on the Gold-Free Integration of Ternary III-As Antimonide Nanowires Directly on Silicon. NANOMATERIALS 2020; 10:nano10102064. [PMID: 33086569 PMCID: PMC7603276 DOI: 10.3390/nano10102064] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 09/26/2020] [Accepted: 09/27/2020] [Indexed: 01/11/2023]
Abstract
During the last few years, there has been renewed interest in the monolithic integration of gold-free, Ternary III–As Antimonide (III–As–Sb) compound semiconductor materials on complementary metal-oxide-semiconductor (CMOS)—compatible silicon substrate to exploit its scalability, and relative abundance in high-performance and cost-effective integrated circuits based on the well-established technology. Ternary III–As–Sb nanowires (NWs) hold enormous promise for the fabrication of high-performance optoelectronic nanodevices with tunable bandgap. However, the direct epitaxial growth of gold-free ternary III–As–Sb NWs on silicon is extremely challenging, due to the surfactant effect of Sb. This review highlights the recent progress towards the monolithic integration of III–As–Sb NWs on Si. First, a comprehensive and in-depth review of recent progress made in the gold-free growth of III–As–Sb NWs directly on Si is explicated, followed by a detailed description of the root cause of Sb surfactant effect and its influence on the morphology and structural properties of Au-free ternary III–As–Sb NWs. Then, the various strategies that have been successfully deployed for mitigating the Sb surfactant effect for enhanced Sb incorporation are highlighted. Finally, recent advances made in the development of CMOS compatible, Ternary III–As–Sb NWs based, high-performance optoelectronic devices are elucidated.
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Parakh M, Johnson S, Pokharel R, Ramaswamy P, Nalamati S, Li J, Iyer S. Space charge limited conduction mechanism in GaAsSb nanowires and the effect of in situ annealing in ultra-high vacuum. NANOTECHNOLOGY 2020; 31:025205. [PMID: 31553959 DOI: 10.1088/1361-6528/ab47aa] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
In this work, the first observation of the space charge limited conduction mechanism (SCLC) in GaAsSb nanowires (NWs) grown by Ga-assisted molecular beam epitaxial technique, and the effect of ultra-high vacuum in situ annealing have been investigated. The low onset voltage of the SCLC in the NW configuration has been advantageously exploited to extract trap density and trap distribution in the bandgap of this material system, using simple temperature dependent current-voltage measurements in both the ensemble and single nanowires. In situ annealing in ultra-high vacuum revealed significant reduction in the trap density from 1016 cm-3 in as-grown NWs to a low level of 7 × 1014 cm-3 and confining wider trap distribution to a single trap depth at 0.12 eV. A comparison of current conduction mechanism in the respective single nanowires using conductive atomic force microscopy (C-AFM) further confirms the SCLC mechanism identified in GaAsSb ensemble device to be intrinsic. Higher current observed in current mapping by C-AFM, increased 4 K photoluminescence (PL) intensity along with reduced full-width half maxima and more symmetric PL spectra, and reduced asymmetrical broadening with increased TO/LO mode in room temperature Raman spectra for in situ annealed NWs again attest to effective annihilation of traps leading to the improved optical quality of NWs compared to as-grown NWs. Hence, the I-V-T analysis of the SCLC mechanism has been demonstrated as a simple approach to obtain information on growth induced traps in the NWs.
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Affiliation(s)
- Mehul Parakh
- Nanoengineering, Joint School of Nanoscience and Nanoengineering, North Carolina A&T State University, Greensboro, NC 27401, United States of America
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Ren D, Ahtapodov L, van Helvoort ATJ, Weman H, Fimland BO. Epitaxially grown III-arsenide-antimonide nanowires for optoelectronic applications. NANOTECHNOLOGY 2019; 30:294001. [PMID: 30917343 DOI: 10.1088/1361-6528/ab13ed] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Epitaxially grown ternary III-arsenide-antimonide (III-As-Sb) nanowires (NWs) are increasingly attracting attention due to their feasibility as a platform for the integration of largely lattice-mismatched antimonide-based heterostructures while preserving the high crystal quality. This and the inherent bandgap tuning flexibility of III-As-Sb in the near- and mid-infrared wavelength regions are important and auspicious premises for a variety of optoelectronic applications. In this review, we summarize the current understanding of the nucleation, morphology-change and crystal phase evolution of GaAsSb and InAsSb NWs and their characterization, especially in relation to Sb incorporation during growth. By linking these findings to the optical properties in such ternary NWs and their heterostructures, a brief account of the ongoing development of III-As-Sb NW-based photodetectors and light emitters is also given.
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Affiliation(s)
- Dingding Ren
- Department of Electronic Systems, Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim, Norway
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Gao Z, Sun J, Han M, Yin Y, Gu Y, Yang ZX, Zeng H. Recent advances in Sb-based III-V nanowires. NANOTECHNOLOGY 2019; 30:212002. [PMID: 30708362 DOI: 10.1088/1361-6528/ab03ee] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Owing to the high mobility, narrow bandgap, strong spin-orbit coupling and large g-factor, Sb-based III-V nanowires (NWs) attracted significant interests in high speed electronics, long-wavelength photodetectors and quantum superconductivity in the past decade. In this review, we aim to give an integrated summarization about the recent advances in binary as well as ternary Sb-based III-V NWs, starting from the fundamental properties, NWs growth mechanism, typical synthetic methods to their applications in transistors, photodetectors, and Majorana fermions detection. Up to now, famous NWs growth techniques of solid-source chemical vapor deposition (CVD), molecular beam epitaxy, metal organic vapor phase epitaxy and metal organic CVD etc have been adopted and developed for the controllable growth of Sb-based III-V NWs. Several parameters including heating temperature, III/V ratio of source materials, growth temperature, catalyst size and kinds, and growth substrate play important roles on the morphology, position, diameter distribution, growth orientation and crystal phase of Sb-based III-V NWs. Furthermore, we discuss the photoelectrical applications of Sb-based III-V NWs such as field-effect-transistors, tunnel diode, low-power inverter, and infrared detectors etc. Importantly, due to the strongest spin-orbit interaction and giant g-factor among all III-V semiconductors, InSb with the geometry of one-dimension NW is considered as the most promising candidate for the detection of Majorana fermions. In the end, we also summarize the main challenges remaining in the field and put forward some suggestions for the future development of Sb-based III-V NWs.
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Affiliation(s)
- Zhaofeng Gao
- Shenzhen Research Institute of Shandong University, Shenzhen, 518057, People's Republic of China. School of Microelectronics, Shandong University, Jinan, 250100, People's Republic of China
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Sharma M, Ahmad E, Dev D, Li J, Reynolds CL, Liu Y, Iyer S. Improved performance of GaAsSb/AlGaAs nanowire ensemble Schottky barrier based photodetector via in situ annealing. NANOTECHNOLOGY 2019; 30:034005. [PMID: 30212376 DOI: 10.1088/1361-6528/aae148] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
In this work, we report on the p-i GaAsSb/AlGaAs nanowires (NWs) ensemble device exhibiting good spectral response up to 1.1 μm with a high responsivity of 311 A W-1, an external quantum efficiency of 6.1 × 104%, and a detectivity of 1.9 × 1010 Jones at 633 nm. The high responsivity of the NWs has been attributed to in situ post-growth annealing of GaAsSb axial NWs in the ultra-high vacuum. The enabling growth technology is molecular beam epitaxy for the Ga-assisted epitaxial growth of these NWs on Si (111) substrates. Room temperature Raman spectra, as well as temperature dependent micro-photoluminescence peak analysis indicated suppression of band tail states and non-radiative channels due to annealing. A similar improvement in in situ annealed p-i GaAsSb NW ensemble with an AlGaAs passivating shell was inferred from a reduction in the Schottky barrier height as well as the NW resistance compared to the as-grown NW ensemble. These results demonstrate in situ annealing of nanowires to be an effective pathway for improving the optoelectronic properties of the NWs and the device thereof.
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Affiliation(s)
- Manish Sharma
- Joint School of Nanoscience and Nanoengineering, North Carolina A&T State University, Greensboro, NC 27401, United States of America
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Zhang J, Tang J, Kang Y, Lin F, Fang D, Wang D, Fang X, Wang X, Wei Z. Structural and spectroscopy characterization of coaxial GaAs/GaAsSb/GaAs single quantum well nanowires fabricated by molecular beam epitaxy. CrystEngComm 2019. [DOI: 10.1039/c9ce00660e] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Through the growth and characterization of GaAs/GaAs0.75Sb0.25/GaAs SQW nanowires, an emission wavelength of about 1.2 μm is achieved.
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Affiliation(s)
- Jian Zhang
- State Key Laboratory of High Power Semiconductor Lasers
- Changchun University of Science and Technology
- Changchun 130022
- China
| | - Jilong Tang
- State Key Laboratory of High Power Semiconductor Lasers
- Changchun University of Science and Technology
- Changchun 130022
- China
| | - Yubin Kang
- State Key Laboratory of High Power Semiconductor Lasers
- Changchun University of Science and Technology
- Changchun 130022
- China
| | - Fengyuan Lin
- State Key Laboratory of High Power Semiconductor Lasers
- Changchun University of Science and Technology
- Changchun 130022
- China
| | - Dan Fang
- State Key Laboratory of High Power Semiconductor Lasers
- Changchun University of Science and Technology
- Changchun 130022
- China
| | - Dengkui Wang
- State Key Laboratory of High Power Semiconductor Lasers
- Changchun University of Science and Technology
- Changchun 130022
- China
| | - Xuan Fang
- State Key Laboratory of High Power Semiconductor Lasers
- Changchun University of Science and Technology
- Changchun 130022
- China
| | - Xiaohua Wang
- State Key Laboratory of High Power Semiconductor Lasers
- Changchun University of Science and Technology
- Changchun 130022
- China
| | - Zhipeng Wei
- State Key Laboratory of High Power Semiconductor Lasers
- Changchun University of Science and Technology
- Changchun 130022
- China
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