Simulation of photovoltaic efficiency of a tandem solar cell on Si with GaN nanowires as an emitter layer

Modeling of photovoltaic properties of multi-junction solar cells integrated on a Si substrate with an array of GaN nanowires as a top emitter has been carried out. Very good antireflection properties of the structure are demonstrated theoretically: the calculated reflectance is lower than 3% for both GaN nanowires/Si and GaN nanowires on GaPN/Si cells. According to our simulations, basic GaN nanowires on Si cell with optimised parameters (doping and NWs morphology) provides energy conversion efficiency of 20%. The approach demonstrates high potential of the GaPN(As)-based multi-junction lattice matched with Si solar cells using an array of GaN nanowires as a top emitter.