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

InAs epilayers with thicknesses of 400, 500, 750, and 1500 nm were grown on GaAs by molecular beam epitaxy and their properties were investigated by r eflection high-energy electron diffraction and photo luminescence (PL). For all InAs epilayers, the PL peak position measured at 10 K is blue-shifted from that of bulk InAs, which could be largely due to the residual strain i n 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-mum thick InAs epilayers grown on GaAs substrate. While the PL p eak position of 400 nm thick InAs layer is linearly blue-shifted toward hig her energy with increase in excitation intensity ranging from 10 to 140 mW, those of thicker InAs epilayers are gradually blue-shifted and then, satur ated above a power of 75 mW. (C) 2002 Elsevier Science B.V. All rights rese rved.