INVESTIGATION OF THE GROWTH TECHNIQUE DEPENDENCE ON THE OPTICAL-PROPERTIES OF SI1-XGEX ALLOY LAYERS

The discrepancy between the measured photoluminescence spectra of Si1- xGex strained alloy layers originating from molecular beam epitaxy (MB E) and chemical vapor deposition (CVD) processes is investigated. Shar p excitonic band edge luminescences are observed for films by both gro wth techniques. For certain films grown by MBE, the photoluminescence spectra contain an additional broad alloy band luminescence at low ene rgy. Deuterium passivation of the MBE layers is shown to annihilate th e broad band luminescence and to increase the band edge luminescence i ntensity. These results are compared with the more intense band edge l uminescence signals from CVD layers for which abundant hydrogen radica ls are usually present during the deposition.