PHOTOLUMINESCENCE MEASUREMENTS FOR GAAS GROWN ON SI(100) AND SI(111) BY MOLECULAR-BEAM EPITAXY

Photoluminescence measurements have been used to characterize Si-doped GaAs layers, ranging in thickness from 1.1-8.1 mu-m, grown on Si(111) and misorientated Si(100) substrates by molecular beam epitaxy. 4.2 K PL spectra for GaAs/Si (100) show a strain-induced splitting between the heavy and light hole valence bands which corresponds to a biaxial tensile stress of 2.8 +/- 0.15 kbar acting on the GaAs layer. Similar measurements for GaAs/Si(111) indicate that the GaAs layer is subject to a biaxial tensile stress of 3.9 +/- 0.15 kbar at 4.2 K. Furthermore, the intensity and line shape of luminescence features for GaAs/Si(111) for the first time indicate a crystalline quality comparable with the best GaAs/Si(100) material.