Optical properties of InAs epilayers grown on GaAs by molecular beam epitaxy

InAs epilayers with thicknesses of 400, 500, 750, and 1500nm were grown on GaAs by molecular beam epitaxy and their properties were investigated by reflection high-energy electron diffraction and photoluminescence (PL). For all InAs epilayers, the PL peak position measured at 10K is blue-shifted from that of bulk InAs, which could be largely due to the residual strain in the epilayer. InAs epilayers have PL peaks red-shifted to lower energy as the thickness of InAs layer is increased. This is the first observation on PL of sub-μm thick InAs epilayers grown on GaAs substrate. While the PL peak position of 400nm thick InAs layer is linearly blue-shifted toward higher energy with increase in excitation intensity ranging from 10 to 140mW, those of thicker InAs epilayers are gradually blue-shifted and then, saturated above a power of 75mW.