Resonant photoluminescence excitation in GaAs grown directly on Si

Abstract
We describe new results observed during resonant excitation in the excitonic region of GaAs grown directly on Si by organometallic vapor phase epitaxy. Two resolved features were found in the light‐hole photoluminescence (PL) region, one identified with a free‐exciton process and the other with donor‐related transitions. Inhomogeneous line broadening was observed for the excitonic PL lines and related to stress fluctuations. Features which track the laser excitation line were observed and identified with a process in which a donor is excited from the n=1 ground state to an n=2 state.