Wide-gap a-SiC:H solar cells with graded absorption layer for triple cell applications

Theoretical and experimental studies were performed to explore the effect of band gap profiling on the performance of wide-gap a-SiC:H cells. The theoretical study was conducted using Advanced Semiconductor Analysis (ASA) to analyze the characteristics of a-SiC:H cell with various types of band gap profiling. We calculated three types of band gap profiling, the U-shape with one-step staircase front and back grading, the U-shape with two-step staircase front and back grading, and the V-shape with linearly graded i-layer. For the case of the U-shape band gap profiling, from both numerical and experimental studies, it was found that the optimum performance can be obtained for an asymmetrical U-shape with the band gap minimum close to the p/i interface. These results reveals that an optimum design of band gap profile leads to an improvement in the performance of a-SiC:H solar cells.