INFLUENCE OF PHOTON RECYCLING ON SOLAR-CELL EFFICIENCIES

A simple model of a homojunction solar cell is improved by taking into account the effect of photon recycling. The efficiency of converting solar radiation into electricity is studied as a function of the key v ariables. Some of these can be directly controlled, e.g. the semicondu ctor layer thickness and the surface recombination velocity. Other var iables can be controlled indirectly, by doping, thermal treatments, et c: the internal efficiency of the radiative emission, the carrier life time and the minority carrier diffusion coefficient. For actual GaAs s olar cells, taking photon recycling into consideration leads to an inc rease in efficiency of the order of 2%. The results we show are useful for the design and fabrication of solar cells based on wide-gap semic onductors.