AbstractHigh and low bandgap amorphous silicon thin film alloys (a-Si:Al, a-Si:Se, a-Si:S, and a-Si:Ga) were prepared by plasma-enhanced chemical vapor deposition. It was found that Al and Ga amorphous silicon alloys are low bandgap materials whereas a:SiS and a:SiSe are high bandgap semiconductors. The optical band gap of these systems could be changed from 1.0 eV to 2.0 eV, depending on the alloying element and its concentration in the film. The dark to light conductivity ratio was measured. The elemental content and distribution was analyzed by the SIMS and EPMA techniques. The results show that some of the amorphous silicon alloys studied are promising materials for multi-bandgap photovoltaic devices.
Modelling spectral irradiation effects on single- and multijunction amorphous silicon photovoltaic devices