BIAXIAL COMPRESSION IN GAAS THIN-FILMS GROWN ON SI

Using X-ray diffraction, transmission electron microscopy and low temp erature photoluminescence, we investigated the interfacial strain acco mmodation of the MBE grown thin (0.3-2 mu m) films of GaAs on (001)Si substrates. When heavily As-doped Si buffer layers were used, the GaAs -on-Si films displayed biaxial compression rather than tension and sma ller unit-cell volumes as compared with that expected from elastically compressed GaAs bulk single crystal. As a result of studying of the b iaxial stress influence on the PL spectra of GaAs, we proposed a new i dentification of PL bands in GaAs-on-Si. The effect of rapid and slow thermal annealing is also investigated.