Temperature Variation of Optical Energy Gap for GaSb-InSb Alloys

Reasonably homogeneous, polycrystalline, solid ingots of GaSb-InSb alloys have been produced by slow directional freezing techniques, as described previously. For alloys of various compositions, normal absorption measurements have been made to determine the variation of optical energy gap Eg with temperature in the range 100-800°K. It is found that alloys show a linear variation of Eg with temperature, and values of extrapolated absolute zero energy gap and energy gap temperature coefficient are obtained. These results are compared with the data from electrical measurements described previously and the question of the variation with composition of the band form of the alloys is discussed.