Numerical modeling of photovoltaic efficiency of n-type GaN nanowires on p-type Si heterojunction

In this Letter, we investigate the photovoltaic properties of heterojunction solar cells based on n-GaN nanowire (NW)/ p-Si substrate heterostructures by means of numerical modeling. Antireflection properties of the NW array on the top of Si substrate were studied theoretically to show an order of magnitude enhancement in antireflection properties in comparison to the pure Si surface (2.5% vs. 33.8%). In order to determine the optimal morphology and doping levels of the structure with maximum possible efficiency we simulated its properties. The carried out simulation showed that the maximum efficiency should be more than 20% under AM1.5D illumination. The proposed design opens new perspectives and opportunities in the field of heterojunction tandem solar cell researches. Schematic view of heterojunction GaN nanowires/Si substrate solar cell. (© 2015 WILEY-VCH Verlag GmbH &Co. KGaA, Weinheim)