Mathematical optimization of photovoltaic converters for diode lasers

The mathematical optimization of vertical-junction photovoltaic converters for use with diode laser arrays supplying powers up to 1 MW is discussed. Photovoltaic parameters were optimized using a mathematical model. The optimized converters have 500 single junctions connected in series. The efficiency varies from 41 percent for a 0.73-micron diode laser to 46 percent for a 0.83-micron diode laser. The optimum width of the single-junction converter is small, 3.0 microns, in order for the p-n junction to be within a diffusion length of the light-generated carriers. Another critical parameter is the series resistance; the optimum value of 0.001 ohms should be achievable. Another critical parameter is the donor carrier concentration, for which an optimum value of 5 x 10 to the 15th carriers/cu cm has been chosen.