Efficiency calculations of heterojunction solar energy converters

A theoretical evaluation of the maximum attainable solar conversion efficiencies of p-n and n-p heterodiodes is presented. The calculations are made for some of the theoretically efficient and feasible heterojunctions of IV and III-V group semiconductors. In these calculations, the Anderson diffusion model is used and carrier concentrations of the two semiconductors are so chosen that photo-carriers generated do not have to surmount any junction barrier. The calculated efficiencies are compared with the reported experimental values and with the conventional Si photovoltaic cell.