Band Gap Energy and Its Temperature Dependence of GaInAsSb Quaternary Alloy Grown by Molecular Beam Epitaxy

Room temperature band gap energies of MBE-grown Ga_1-x In_xAs_1-y Sb_y have been determined from Fourier transform infrared spectroscopy measurements. The results show good agreement with those calculated from a semi-empirical interpolation method. The temperature dependence of band gap energy has also been investigated for an alloy sample with zd.247 and yd.907 at temperatures ranging from 10 to 300 K. While the energy gap varies approximately linearly with temperature for T > 100 K, with a temperature coefficient dE_g/dT of -2.63x10^-4 eV. K^-1 , a nearly quadratic T-dependence of the band-gap shift exists for temperatures below the Debye temperature, which consists with that of most of semiconductors.