Simulation of the characteristics of InGaAs/InP-based photovoltaic laser-power converters

A method for mathematical simulation is used to analyze the efficiencies attainable in photovoltaic laser-power conversion at wavelengths of 1.3 and 1.55 $\mu$m in In$_{0.53}$Ga$_{0.47}$As/InP heterostructures with light input on the side of the $n$-InP substrate. The influence exerted on the efficiency by the parameters of the In$_{0.53}$Ga$_{0.47}$As/InP heterostructure and by the design of the photovoltaic laser-power converter is examined. The simulated characteristics of In$_{0.53}$Ga$_{0.47}$As/InP photovoltaic converters are compared with those of GaAs-based photovoltaic converters for a wavelength of 809 nm. It is shown that efficiencies of 40% at a wavelength of 1.3 $\mu$m and nearly 50% at 1.55 $\mu$m can be attained at a laser power of about 2–6 W, but the efficiency noticeably decreases at higher laser-light intensities. It is found that the main factor that hinders the achievement of a high efficiency in the conversion of high-intensity laser light is loss in the $n$-InP substrate. The optimal doping level of $n$-InP substrates to be used in the photovoltaic converters intended for varied laser-light intensities is estimated.