Diagnostics of GaAs epitaxial layers grown on silicon substrates by photoluminescence and DLTS methods

Silicon-doped and silicon-nondoped GaAs layers grown on silicon substrates by two-step technology are investigated through measurements of photoluminescence (T=4.5 K) and unsteady-state bulk spectroscopy. The obtained results are compared with corresponding data for homoepitaxial structures. The performed analysis allows to identify the basic photoluminescence bands of active layers of homo- and heteroepitaxial structures and to determine the nature of the main small acceptor. In addition, the value of thermal stresses and content of deep centers in GaAs/Si layers are estimated