Melt growth of quasi-binary (GaSb)1−x(InAs)x crystals (original) (raw)
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Strong band gap narrowing in quasi-binary (GaSb)1−x(InAs)x crystals grown from melt
Journal of Crystal Growth, 1999
Large crystals of a quasi-binary semiconductor alloy (GaSb) \V (InAs) V with x "0.02-0.05 have been grown from melt for the first time. The family of quasi-binary crystals (GaSb) \V (InAs) V grown and reported here are different from the conventional Ga \V In V As W Sb \W quaternaries due to growth behavior and physical properties. Significant narrowing of the band gap was observed in these crystals compared to the conventional quaternary Ga \V In V As W Sb \W (with x"y). With an InAs content of about 2-5 at%, band gaps in the range of 0.6-0.65 eV have been demonstrated. The possible origins of the band gap narrowing (i.e., high bowing parameter) include chemical and structural alterations in the grown crystals, resulting from the association of Ga-Sb and In-As in the melt. 0022-0248/99/$ -see front matter 1999 Elsevier Science B.V. All rights reserved. PII: S 0 0 2 2 -0 2 4 8 ( 9 8 ) 0 0 9 4 6 -4
The European Physical Journal B - Condensed Matter, 2003
Pseudopotential investigation of energy band gaps and charge distribution in quasibinary (GaSb)1−x(InAs)x crystals has been reported. To the best of our knowledge, there had been no reported theoretical work on these materials. In agreement with experiment, the quasi-binary crystals of interest showed a significant narrowing of the optical band gap compared to the conventional GaxIn1−xAsySb1−y quaternary alloys (with x = 1 − y). Moreover, the absorption at the optical gaps indicated that (GaSb)1−x(InAs)x is a direct Γ to Γ band-gap semiconductor within a whole range of the x composition. The information derived from the present study predicts that the band gaps cross very important technological spectral regions and could be useful for thermophotovoltaic applications.
High-Quality GaInAsSb and GaAlAsSb Layers for Thermophotovoltaics Grown by Liquid-Phase Epitaxy
Solid State Phenomena, 2010
GaSb based III-V heterostuctures are attractive for optoelectronic devices such as midin- frared lasers, detectors, and thermophotovoltaics (TPVs). In this paper the growth and characterization of GaInAsSb and GaAlAsSb quaternary layers, lat-tice-matched to GaSb substrate, are reported, with a particular focus on these alloys for TPV devi-ces. High-quality with a mirror-like surface morphology epilayers Ga1-x InxAsy Sb1-y with In content x in the range 0.1-0.22 and Ga1-xAlxAsySb1-y layers with Al content up to 0.3 in the solid are grown by Liquid-Phase Epitaxy (LPE) from In- and Ga-rich melt, respectively. The compositions of the quaternary compounds are determined by X-ray microanalysis. The crystalline quality of GaInAsSb/ GaSb and GaAlAsSb/GaSb heterostuctures is studied by X-ray diffraction (XRD) and transmission electron microscopy (TEM) measurements.
Crystal growth and characterization of I-IV2-V3 semiconductor compounds and alloys based thereon
1985
The existence of various ternary adamantine compounds is discussed. Normal and defect ternary adamantine compounds have been a subject of discussion, p a r t icu la r ly from a structural point of view. Rules for the formation of adamantine compounds are explained and related to each other. A home-made DTA apparatus was operated to detect the melting point and phase change from room temperature up to 1300 °C for the materials investigated. The group I-IV2-V3 compounds were the main subject o f this research. CuGe2 Ps and CuSi2 P3 were the only compounds found to grow in this family. The f i r s t was chosen for study in more d e ta i l , mainly because of i ts lower melting point. CuGe2 P3 was compared to other compounds, part icu la r ly structural aspects, and solid solutions were tr ied for twenty-two d iffe ren t materials. This investigation shows s im ila r ity with group 1 2 -IV-Vs compounds, such as CuzGeSs, and new alloys were found with Cu2 Ge$3 . Stoichiometric Cu2 GeS3 d...
Novel vertical directional solidification process (VDS-process) has been constructed for growth of the III-V detached crystals. Research aim is to grow the gallium ("Ga") doped In (1-x) GaxSb (x=0.10, 0.15, 0.25) ingots. The comprehensive characterization of the composition, structure, electrical, microstructure and the thermoelectric properties by tuning the stoichiometry are studied. The doping in pristine InSb decreased the carrier mobility of the binary InSb ingots from ~6.05x10 4 cm 2 /V.sec to In(1-x)GaSb ~ 1.241x10 4 , 9.01x10 3 , and 2.436x10 3 cm 2 /V.sec, and the resistivity from 3.0x10-3 Ω.cm marginally reduced to 2.98, 2.58, and 1.69 x10-3 Ω.cm. Remarkably, the carrier concentration, increased from ~3.8x10 16 cm 3 to ~1.89, 2.29, and 3.15 x10 18 cm 3 and increase in dislocation density from ~ 962cm-2 in to ~1.21, 6.94 and 9.93x10 3 cm-2. The "Ga" doping tailored the band gap of InSb from 0.169eV to 0.2011, 0.2605 and 0.3011eV, and the increased FWHM from 65arcsec InSb to 103, 124 and 145arcsec for the respective growths. The binary InSb perfect single crystal converted to the perfect ternary crystal and decreased XRD peak intensity of the (022) growth direction by doping "Ga" into InSb. To add, the composition% have been exhibited the point defects and decreased the mobility by one order by doping "Ga", while the electrical resistivity changes marginally. The carrier concentration increased two fold; it promotes increase in the thermo electric power factor and enhancement in ZT value. The "Ga" doping forms the second phase of GaSb at the grain boundaries, which reduces the thermal conductivity, increase dislocations, and carrier concentration. The Ga doping, the electron transport enhances, and is potential for the thermoelectric (TE) materials.
Inorganic Chemistry, 2019
Thermoelectric power generators require semiconductor materials with controlled phonon and free charge carrier transport properties. This could be achieved by changing their molecular and lattice dynamics through introducing/ controlling structural imperfections (defects engineering). The structural imperfections such as point defects and compositional segregations in a multicomponent alloy are observed experimentally, and their impact on electron and phonon transport properties was explained. The thermoelectric properties of a III− V ternary alloy InGaSb was improved by the presence of point defects and compositional segregations. The compositions were segregated randomly, and they had a major impact on the phonon contribution to the thermal conductivity. The point defects affected electrical resistivity, and the Seebeck coefficient was influenced by carrier concentration. The figure of merit (ZT) of In 0.95 Ga 0.05 Sb is enhanced to 0.62 at 573 K, and it is the highest among any other reported values of binary/ternary III−V semiconductor alloys. The enhancement in the ZT of InGaSb from the viewpoints of point defects and compositional segregations are explained. This experimental defect engineering study could be helpful to understand and improve the thermoelectric properties of many other crystalline materials.
Microhardness of Czochralski-Grown Single Crystals of VB2
Journal of Solid State Chemistry, 1997
Single crystals of congruent melting hexagonal VB 2 were grown using a triarc furnace applying the Czochralski technique. Orientation dependent microhardness measurements on a single crystal reveal quasi similar hardness in the crystallographic directions 1 100.12 2 and 1 110.02 2 , whereas the 1 110.12 2 shows slightly lower values.
Crystal growth technology of binary and ternary II–VI semiconductors for photonic applications
Many photonic applications of II-VI semiconductors require thin films that are grown by various epitaxial techniques. However, whenever there is a need for a large interaction length with electromagnetic radiation, bulk crystals are required. Such crystals are also needed as substrates for epitaxy. This paper discusses bulk crystal growth technology of binary and ternary II-VI chalcogenides for such applications. We discuss purification and crystal growth using melt, solution, and vapor-phase techniques that we use for various cadmium and zinc chalcogenides as well as for cadmium-manganese-based semi-magnetic ternary compounds. Further, we discuss transition metal doping in II-VI semiconductor compounds and their applications for building photonic devices like remote laser vibrometers and room temperature operating mid-infrared solid-state lasers. We present our earlier work in these areas and our recent results. r address: arthur226@comcast.net (W. Palosz).
First time, the homogeneous and the entire detached In0.5Ga0.5Sb crystals were grown using the step by step growth process by a vertical directional solidification process (VDS-process). The growth stability, crystal appearance, and growth habit of the In0.5Ga0.5Sb crystals were studied. The composition % 'x' changes showed the conversion n-type to p-type along c-axis. Novel In0.5Ga0.5Sb crystals were exhibited the electron mobility 1.59x104cm2/V.s in n-type region, and the hole mobility increased highest to 935cm2/V.s in p-type region. Indium segregations reduction showed the increased resistivity to 1.1 x10-3 Ω-cm, and decreased dislocation density to 103cm2. The tuned energy band gap 0.16eV to 0.68eV, and microhardness 2.19GPa to 3.98GPa was measured. The entire detached In0.5Ga0.5Sb crystals showed the preferential (022) growth. The axial and the transverse indium segregation was ~0.0802 mol% per mm. In0.5Ga0.5Sb crystal is advantageous, and encompass the electromagnetic spectrum for the infrared devices. The composition % and transport properties of In0.5Ga0.5Sb crystallization significantly enhanced, the causes are studied in this article.