Gallium vacancy and the residual acceptor in undoped GaSb studied by positron lifetime spectroscopy and photoluminescence
TL;DR: In this article, annealing studies were performed to study undoped p-type gallium antimonide materials and a 314 ps positron lifetime component was attributed to Ga vacancy (V-Ga) related defect.
Abstract: Positron lifetime, photoluminescence (PL), and Hall measurements were performed to study undoped p-type gallium antimonide materials. A 314 ps positron lifetime component was attributed to Ga vacancy (V-Ga) related defect. Isochronal annealing studies showed at 300 degreesC annealing, the 314 ps positron lifetime component and the two observed PL signals (777 and 797 meV) disappeared, which gave clear and strong evidence for their correlation. However, the hole concentration (similar to2x10(17) cm(-3)) was observed to be independent of the annealing temperature. Although the residual acceptor is generally related to the V-Ga defect, at least for cases with annealing temperatures above 300 degreesC, V-Ga is not the acceptor responsible for the p-type conduction. (C) 2002 American Institute of Physics.
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TL;DR: In this paper, temperature dependent Hall (TDH) measurements and photoluminescence (PL) measurements were performed on undoped GaSb materials and the acceptor levels were found to be the important acceptor responsible for the p-type nature of the present undoped GASb samples.
Abstract: Undoped GaSb materials were studied by temperature dependent Hall (TDH) measurements and photoluminescence (PL). The TDH data reveals four acceptor levels (having ionization energies of 7meV, 32meV, 89meV and 123meV) in the as-grown undoped GaSb samples. The 32meV and the 89meV levels were attributed to the GaSb defect and the VGa-related defect. The GaSb defect was found to be the important acceptor responsible for the p-type nature of the present undoped GaSb samples because of its abundance and its low ionization energy. This defect was thermally stable after the 500oC annealing. Similar to the non-irradiated samples, the 777meV and the 800meV PL signals were also observed in the electron irradiated undoped GaSb samples. The decrease of the two peaks’ intensities with respect to the electron irradiation dosage reveals the introduction of a non-radiative defect during the electron irradiation process, which competes with the transition responsible for the 777meV and the 800meV PL peaks.
TL;DR: In this article, temperature dependent positron trapping into the VGa-related defect having a characteristic lifetime of 310ps was observed in the as-grown sample, and another lifetime component (280ps) was observed only in the electron irradiated sample but not in the non-irradiated sample.
Abstract: Positron lifetime spectroscopy has been used to study the vacancy type defects in undoped gallium antimonide. Temperature dependent positron trapping into the VGa-related defect having a characteristic lifetime of 310ps was observed in the as-grown sample. The lifetime data were well described by a model involving the thermal ionization (0/-) of the VGa-related defect and its ionization energy was found to be E(0/-)=83meV. For the electron irradiated sample, the VGa-related defect with lifetime of 310ps that was found in the non-irradiated samples was also identified. Moreover, another lifetime component (280ps) was only observed in the electron irradiated sample but not in the non-irradiated sample. It was also attributed to the VGa-related defect. The two identified VGa-related defects should have different microstructures because of their difference in characteristic lifetimes. The 280ps component remains thermally stable after the 500oC annealing while the 310ps component anneals at 300oC.
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TL;DR: The 3-V ternaries and quaternaries (AlGaIn)(AsSb) lattice matched to GaSb is a promising material for high speed electronic and long wavelength photonic devices.
Abstract: Recent advances in nonsilica fiber technology have prompted the development of suitable materials for devices operating beyond 155 mu m The III-V ternaries and quaternaries (AlGaIn)(AsSb) lattice matched to GaSb seem to be the obvious choice and have turned out to be promising candidates for high speed electronic and long wavelength photonic devices Consequently, there has been tremendous upthrust in research activities of GaSb-based systems As a matter of fact, this compound has proved to be an interesting material for both basic and applied research At present, GaSb technology is in its infancy and considerable research has to be carried out before it can be employed for large scale device fabrication This article presents an up to date comprehensive account of research carried out hitherto It explores in detail the material aspects of GaSb starting from crystal growth in bulk and epitaxial form, post growth material processing to device feasibility An overview of the lattice, electronic, transport, optical and device related properties is presented Some of the current areas of research and development have been critically reviewed and their significance for both understanding the basic physics as well as for device applications are addressed These include the role of defects and impurities on the structural, optical and electrical properties of the material, various techniques employed for surface and bulk defect passivation and their effect on the device characteristics, development of novel device structures, etc Several avenues where further work is required in order to upgrade this III-V compound for optoelectronic devices are listed It is concluded that the present day knowledge in this material system is sufficient to understand the basic properties and what should be more vigorously pursued is their implementation for device fabrication (C) 1997 American Institute of Physics
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01 Jan 2003
TL;DR: In this article, the authors compare Positron annihilation with other defect-sensitive techniques, such as defect characterisation in III-V and II-VI compounds, and compare them with other techniques.
Abstract: 1 Introduction.- 2 Experimental Techniques.- 3 Basics of Positron Annihilation in Semiconductors.- 4 Defect Characterization in Elemental Semiconductors.- 5 Defect Characterization in III-V Compounds.- 6 Defect Characterization in II-VI Compounds.- 7 Defect Characterization in Other Compounds.- 8 Applications of Positron Annihilation in Defect Engineering.- 9 Comparison of Positron Annihilation with Other Defect-Sensitive Techniques.- A1 Semiconductor Data.- A2 Trapping Model Equations.- References.
479 citations
TL;DR: The physical properties of GaSb are briefly presented and the device implications reviewed in this paper, where a direct gap semiconductor (0.72 eV) capable of being doped either p or n type with good mobilities and it has significant electrooptical potential in the near IR range.
Abstract: The physical properties of GaSb are briefly presented and the device implications reviewed. GaSb is a direct gap semiconductor (0.72 eV) capable of being doped either p or n type with good mobilities and it has significant electro-optical potential in the near IR range. As a substrate, or active layer, GaSb can be employed in conjunction with many semiconductors such as (AlGa)Sb or In(AsSb) and has interesting heterojunction potential for detectors and lasers and quantum well structures.
184 citations
TL;DR: In this article, an intentionally doped gallium antimonide has been grown by molecular beam epitaxy on gallium arsenide and gallium anti-antimonide, and a strong correlation has been found between the quality of the layers and the degree of excess antimony flux; the best material was obtained with the minimum antimony stable growth at a particular substrate temperature.
Abstract: Unintentionally doped gallium antimonide has been grown by molecular‐beam epitaxy on gallium arsenide and gallium antimonide. Substrate temperatures in the range 480 to 620 °C and antimony to gallium flux ratios from 0.65 : 1 to 6.5 : 1 have been investigated. The deposition conditions have been related to growth morphology and to the electrical and optical properties of the epitaxial films. A strong correlation has been found between the quality of the layers and the degree of excess antimony flux; the best material in terms of both optical and electrical properties was obtained with the minimum antimony stable growth at a particular substrate temperature. All the material exhibited residual p‐type behavior. The lowest hole concentration achieved was 7.8×1015 cm−3 with a corresponding room‐temperature mobility of 950 cm2/V s. The narrowest PL (photoluminescence) features observed were peaks associated with bound exciton transitions with half‐widths of 2–3 meV.
145 citations