Growth and Characterization of InAsxSb1−x Bulk Crystals and Growth Rate Measurements (original) (raw)
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Melt growth of quasi-binary (GaSb)1−x(InAs)x crystals
Journal of Crystal Growth, 1999
] V semiconductor alloys has been synthesized and bulk crystals grown from the melt for the first time. The present investigation is focused on (GaSb) \V (InAs) V (0(x(0.05) due to its importance for thermophotovoltaic applications. The structural properties of this melt-grown quasi-binary alloy are found to be significantly different from the conventional quaternary compound Ga \V In V As W Sb \W with composition x"y. Synthesis and growth procedures are discussed.
Journal of Crystal Growth, 2016
Gallium-free InAs/InAsSb superlattices (SLs) are being actively explored for infrared detector applications owing to their superior carrier lifetimes. However, antimony (Sb) incorporation in InAs layers during growth can significantly alter the properties of the grown material. In this study, using X-ray energy dispersive spectrometry, we quantify the extent of Sb segregation and establish epitaxial parameters for high-quality InAs/InAsSb SL materials. Epitaxial conditions are determined for a nominal 7.7 nm InAs/3.5 nm InAs 0.7 Sb 0.3 SL structure tailored for an approximately six micron response at 150 K. Since the growth of mixed anion alloys is complicated by the potential reaction of As 2 with Sb surfaces, authors varied the deposition temperature (T g) in order to control As 2 surface reactions on Sb surfaces. Authors find that Sb incorporation is suppressed by 21 %, with the increase of T g from 395 to 440 °C. This incorporation likely stems from Sb surface segregation during InAsSb layer growth that is driven by the As-Sb exchange mechanism. The compositional and dimensional changes related to Sb segregation can have significant effects on the long-wavelength threshold and carrier lifetime and merit further studies in order to advance this materials system.
Optical study of narrow band gap InAs x Sb 1−x (x = 0, 0.25, 0.5, 0.75, 1) alloys
The structural, electronic, and optical properties of InAs, InSb, and their ternary alloys InAs x Sb 1−x (x = 0.25, 0.5, 0.75) are investigated within density functional theory utilizing the WIEN2K package. We find that the lattice constants and bulk moduli as a function of x are in best agreement with Vegard's linear rule. When computing the electronic band structures with the modified Becke-Johnson exchange-correlation functional (mBJLDA), our results for the band gaps of InAs, InSb, and their ternary alloys are in good agreement with the available experimental results while the conventional Wu-Cohen generalized gradient approximation (GGA) functional leads to zero or close to zero band gaps. In particular, our mBJLDA results confirm experimental evidence that the minimum band gap occurs for As concentrations around x ≈ 0.3. Furthermore, we investigate the dielectric function of these compounds within the random phase approximation using both the Wu-Cohen GGA and the mBJLDA functionals. While the mBJLDA results of our fully first-principles calculations show good agreement of the peak positions in 2 (ω) with experiments, the peaks in the optical spectra based on the Wu-Cohen GGA band structure appear redshifted compared to experiment. We further identify the interband transitions responsible for the structures in the spectra. Looking at the optical matrix element, we note that the major peaks are dominated by transition from the Sb 5p (As 4p) states to In s states for InSb and InAs 0.25 Sb 0.75 (InAs, InAs 0.75 Sb 0.25 , and InAs 0.5 Sb 0.5).
Electronic properties of unstrained unrelaxed narrow gap InAsxSb1−x alloys
Journal of Physics D: Applied Physics, 2016
The electronic properties of unstrained unrelaxed InAs x Sb1−x alloys have been determined in a wide range of alloy compositions using IR magnetospectroscopy, magnetotransport and IR photoluminescence. All studied alloys have n-type background doping with electron concentration decreasing with the Sb content. The composition dependence of the background doping concentration follows an empirical exponential law in a wide range of compositions. Both bandgap and electron effective mass dependence on alloy composition exhibit negative bowing reaching lowest values at x = 0.63: E g = 0.10 eV, m* = 0.0082 m 0 at 4.2 K. The bowing coefficient of 0.038 m 0 obtained for the electron effective mass is in good agreement with that obtained from the Kane model.
Homogeneous InGaSb crystal grown under microgravity using Chinese recovery satellite SJ-10
npj Microgravity, 2019
Microgravity crystal growth experiment for the growth of In0.11Ga0.89Sb was performed at the Chinese recoverable satellite through the space program SJ-10. This experiment is aimed to understand the melt formation and growth kinetics of InxGa1−xSb solid solution with higher indium composition, because their segregation coefficient was higher than the crystals with lower indium compositions. The target composition and uniformity were achieved with higher growth rate under microgravity, whereas the uniformity in composition was not achieved under normal gravity. The growth and dissolution were affected mainly by the steady state equilibrium in the melt composition because of the convection under normal gravity. The non-steady state equilibrium in the melt composition under microgravity helped to achieve a higher growth rate and compositional homogeneity at higher indium composition of InxGa1−xSb solid solution.
MBE growth of InAs/InAsSb/AlAsSb structures for mid-infrared lasers
Journal of crystal …, 2001
The growth by solid source molecular beam epitaxy (MBE) of type-II InAsSb/InAs multi-quantum well laser diodes on InAs has been studied. Strained InAsSb/InAs quantum wells were sandwiched between two AlAs 0.16 Sb 0.84 2 mmthick cladding layers, lattice-matched to InAs. The precise control of the composition of the thick AlAsSb ternary alloy was obtained using a quasi-stoichiometric growth (QSG) method, which requires a determination of the incorporation rate of each element. This rate was obtained from reflection high-energy electron diffraction (RHEED) intensity oscillations. Alloys composition was entirely controlled by Sb 2 flux, suggesting a sticking coefficient close to unity. Mesa-stripe laser diodes processed from the epitaxied structures operated at 3.5 mm in pulsed regime up to 220 K, with a threshold current density of 130 A/cm 2 at 90 K and a peak optical power efficiency of 50 mW/A/facet.
Structural and Optical Characteristics of Metamorphic Bulk InAsSb
Frontiers in Electronics, 2014
15. NUMBER OF PAGES 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 5c. PROGRAM ELEMENT NUMBER 5b. GRANT NUMBER 5a. CONTRACT NUMBER Form Approved OMB NO. 0704-0188 3. DATES COVERED (From-To)-UU UU UU UU Approved for public release; distribution is unlimited. Structural and Optical Characteristics of Metamorphic Bulk InAsSb Bulk unrelaxed InAsSb alloys with Sb compositions up to 65% and layer thicknesses up to 3 ?m were grown by molecular beam epitaxy. The photoluminescence (PL) peak energy as low as 0.10 eV was demonstrated at T = 77 K. The electroluminescence and quantum efficiency data demonstrated with unoptimized barrier heterostructures from T = 80 to 150 K suggested large absorption and carrier lifetimes sufficient for the development of long wave infrared detectors and emitters with high quantum efficiency. The minority hole transport was found to be adequate for development of the The views, opinions and/or findings contained in this report are those of the author(s) and should not contrued as an official Department of the Army position, policy or decision, unless so designated by other documentation.
Structural properties of InAs/InAs1–xSbx type-II superlattices grown by molecular beam epitaxy
Journal of Vacuum Science & Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phenomena, 2012
Strain-balanced InAs/InAs1−xSbx type-II superlattices (SLs) have been proposed for possible long-wavelength infrared applications. This paper reports a detailed structural characterization study of InAs/InAs1−xSbx SLs with varied Sb composition grown on GaSb (001) substrates by modulated and conventional molecular beam epitaxy (MBE). X-ray diffraction was used to determine the SL periods and the average composition of the InAs1−xSbx alloy layers. Cross-section transmission electron micrographs revealed the separate In(As)Sb/InAs(Sb) ordered-alloy layers within individual InAs1−xSbx layers for SLs grown by modulated MBE. For the SLs grown by conventional MBE, examination by high-resolution electron microscopy revealed that interfaces for InAs1−xSbx deposited on InAs were more abrupt, relative to InAs deposited on InAs1−xSbx: this feature was attributed to Sb surfactant segregation occurring during the SL growth. Overall, these results establish that strain-balanced SL structures with...
Growth and characterization of InAs/GaSb photoconductors for long wavelength infrared range
Applied Physics Letters, 1997
In this letter we report the molecular beam epitaxial growth and characterization of InAs/GaSb superlattices grown on semi-insulating GaAs substrates for long wavelength infrared detectors. Photoconductive detectors fabricated from the superlattices showed photoresponse up to 12 m and peak responsivity of 5.5 V/W with Johnson noise limited detectivity of 1.33ϫ10 9 cm Hz 1/2 /W at 10.3 m at 78 K. © 1997 American Institute of Physics. ͓S0003-6951͑97͒03236-1͔