Detailed study of Ga low compositional substitution by In in polycrystalline GaSb



In the last decade GaSb based semiconductors have attracted great scientific interest as a promising material for thermophotovoltaic (TPV) applications. Among them, the ternary semiconductors Ga1–xInxSb are preferred because their bandgap, varying from 0.72 eV (GaSb) to 0.18 eV (InSb), suits the emission wavelength band of low temperature (1000–1400 ºC) non-wavelength selective TPV radiator. The aim of the present work is to study some physical properties of the ternary semiconductor Ga1–xInxSb, by varying its In content, in the vicinity of the binary GaSb. The ingots were grown by the vertical Bridgman method. The stoichiometry and homogeneity of the samples were checked using EDS analysis and the samples were found to be homogeneous having a stoichiometry very close to the nominal one. The TEM observation shows a high density of small clusters having their density and size almost the same in all samples. Infrared Spectroscopy reveals that the optical phonon behaviour occurred, was one mode and there is a weak compositional dependence of phonon parameters. Both the structural as well as the spectroscopic investigation do not detect any kind of ordering during the substitution of Ga by the In atoms. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)