Empirical expression for the composition and temperature dependence of the energy gap in InAlSb

An empirical expression for the energy bandgap as a function of alloy composition x and temperature for In1−xAlxSb was reported. The In1−xAlxSb epitaxial layers were grown by molecular beam epitaxy (MBE) on InSb(1 0 0) substrate, utilizing a p+-p+-n-n+ structure. High resolution X-ray diffraction was used to characterize the epitaxial layers. The Al composition of 2.8% was obtained by assuming the Bragg's formula and Vegard's law. Spectral response measurement of the diodes has been employed to investigate the temperature dependence of the band gap of In1−xAlxSb alloys in the range between 77 K and 260 K. The calculated results for energy gap of InAlSb were in good agreement with the available data and our experimental observation.