Heteroepitaxy of GaAs on Si: The effect of <i>i</i> <i>n</i> <i>s</i> <i>i</i> <i>t</i> <i>u</i> thermal annealing under AsH3

Abstract

This letter shows that an in situ thermal annealing step in AsH3/H2 during the metalorganic vapor phase epitaxy of GaAs on Si(001) improves the crystalline quality. The dislocation density is reduced (below 107 cm−2) without affecting the Si diffusion across the heterointerface or the strain level in the epilayer. The nature of the various near-band-gap recombinations present in the unannealed and annealed samples is discussed in light of selective photoluminescence experiments.