Design and optimization of GaAs photovoltaic converter for laser power beaming

GaAs photovoltaic (PV) converters are useful for the conversion of monochromatic light into electrical power in numerous military and industrial applications. The work of this paper is to design a monochromatic GaAs PV converter for coupling to laser beams in the wavelength of 790-840 nm and optimize its structure, layer thicknesses, doping levels of the emitter and base, and antireflection coating. Modeling calculations of the GaAs PV converter optimization are carried out using PC-1D. From the highest efficiency point of view, the best wavelength is 840 nm at which the optimized structure gives an efficiency of 61.8% theoretically. Experiment results under 808 nm laser power beaming show that high optical-to-electrical conversion efficiency of 53.23% at 5 W/cm2 is achieved using the optimized GaAs PV laser converter. Finally, accurate extraction of the key parameters, viz. the ideality factor, reverse saturation current, series resistance and shunt resistance is introduced. Variations of these parameters with illumination intensity are also investigated analytically based on the one diode model, which are necessary for the design of a high performance PV generation system.