Finite element simulations of compositionally graded InGaN solar cells

The solar power conversion efficiency of compositionally graded InxGa1 xN solar cells was simulated using a finite element approach. Incorporating a compositionally graded region on the InGaN side of a p-GaN/n-InxGa1 xN heterojunction removes a barrier for hole transport into GaN and increases the cell efficiency. The design also avoids many of the problems found to date in homojunction cells as no ptype high-In content region is required. Simulations predict 28.9% efficiency for a p-GaN/n-InxGa1 xN/ n-In0.5Ga0.5N/p-Si/n-Si tandem structure using realistic material parameters. The thickness and doping concentration of the graded region was found to substantially affect the performance of the cells. & 2009 Elsevier B.V. All rights reserved.