Simulation-Optimized ZnS_xSe_1-x Contacts on Si for Photovoltaic Carrier-Selective Contacts

ZnS_xSe_1-x films are promising materials for front carrier-selective contacts in silicon photovoltaics given their wide bandgaps and low resistivities compared to amorphous silicon, with the potential to capture more photo-generated current than a traditional heterojunction with intrinsic thin layer (HIT) solar cell. X-ray photoelectron and ellipsometric spectra of ZnS_xSe_1-x (x ranging from 0 to 1) films grown on Si by molecular beam epitaxy were used to measure band offsets of ZnS_xSe_1-x with respect to Si for purposes of accurate optoelectronic simulations of photovoltaic devices incorporating ZnS_xSe_1-x carrier-selective contacts. Further experimentally determined parameters including complex refractive index and resistivity were also included in the simulation of a HIT-style cell to determine the ZnS_xSe_1-x top contact mole fraction x, doping level, and thickness for optimal device performance.