Temperature dependence of photoreflectance measurements in InAs epitaxial layers

Photoreflectance (PR) spectra were measured for different temperatures within the range from 78 K to 287 K. The obtained PR spectra of both LPE and VPE grown samples measured at different temperatures show Franz-Keldysh oscillations near the bandgap . These spectra are well fitted with the cosine function approximation. The behaviour of with temperature is shown to be temperature-range dependent. varies linearly with temperatures above 150 K while this is not the case when T falls below 150 K. The obtained values for the energy bandgap , the temperature coefficient and the spin-orbit splitting are compared with the published data in the literature.