Photoluminescence spectroscopy was used to study Si incorporation into polar GaAs on non-polar Ge substrates. Shifts of the photoluminescence spectra towards higher energies occurred with increasing growth temperature, and increasing trimethylgallium or AsH3 mole fractions. The full-width at half-maximum also increased. A peak at 1.49eV was attributed to a band-to-acceptor transition which involved residual C. The photoluminescence peak energy shifted towards higher energies with increasing growth temperature, due to an increase in the electron concentration. A vacancy model was suggested to explain the photoluminescence shift towards higher energy with increasing AsH3 mole fraction. The photoluminescence peak shifted towards higher energies with increasing trimethylgallium mole fraction. Out-diffusion of Ge into the GaAs epitaxial layer could hardly be detected in the secondary ion mass spectroscopy results.

M.K.Hudait, P.Modak, S.Hardikar, S.B.Krupanidhi: Journal of Applied Physics, 1998, 83[8], 4454-51