Simulation and optimization of InGaN Schottky solar cells to enhance the interface quality

摘要

The InGaN/GaN Schottky solar cell was numerically investigated under AM1.5 illuminations using Silvaco-Atlas software to reach high efficiencies. According to the simulation results, when the indium composition (x_(In)) exceeds 54%, the conversion efficiency drops sharply and a large valence band offset appears. This failure can be explained by the recombination of the generated carriers before their collection due to the large lattice mismatch in high indium compositions. To overcome this inability, an effective process is established to ameliorate the interface between n-InGaN and n-GaN and to enhance the Schottky solar cell performances. The obtained results predict a clear enhancement of the efficiency from 2.25% to 18.48% at x_(In) = 60%. An optimization of this structure achieves an important efficiency of 21.69% for the optimal value of x_(In) = 54%, metal work function W_f = 6.3 eV, doping concentration N_d = 2 × 10~(17) cm~(-3) and an InGaN layer thickness T_(InGaN) = 0.18 μm.