Design of n-AlInN on p-silicon heterojunction solar cells

Abstract: Aluminum Indium Nitride (AlInN) alloys offer great potential for photovoltaic devices thanks to their wide direct bandgap energy that covers the solar spectrum from 0.7 eV (InN) to 6.2 eV (AlN), and their superior resistance to high temperatures and high-energy particles. In this paper, we report the design of AlInN on silicon heterojunctions, with the aim to explore their potential for solar cell devices through the analysis and optimization of the properties of the AlInN on Si heterojunction. In particular, we study the influence of the AlInN bandgap energy, AlInN thickness and carrier concentration, silicon surface recombination, interface defects and Si wafer quality on the photovoltaic properties (conversion efficiency and external quantum efficiency) of the AlInN on Si heterojunctions. The effect of introducing an anti-reflective coating is also studied. Optimized AlInN on Si heterostructure shows a conversion efficiency of 18% under 1-sun AM1.5G illumination for low-quality Si wafers, which increases to 23.6% for high-quality Si wafers and incorporating a properly designed anti-reflective layer. In comparison with standard Si solar cells without AlInN, the external quantum efficient of the devices increases for wavelengths below 500 nm, making them appealing for space applications. These results lead to the AlInN on Si heterojunction a promising future as a novel technology for solar cell devices.