Determining the band gap of GaxIn1-xAsySb1-y quaternary alloy by infrared ellipsometric spectroscopy

The refractive index spectra of Ga x In 1- x As y Sb 1- y MBE epitaxy layers above, near and below the band gap were studied by room temperature infrared ellipsometric spectroscopy with different compositions. The band gaps were determined by refractive enhancement. It was found that the band gap energy changes approximately linearly as a function of composition between x =0.2~0.3.