Effect of I/N interface on the performance of superstrate hydrogenated microcrystalline silicon solar cells

A study on the effect of the n-type hydrogenated amorphous silicon (a-Si:H) buffer layers at the I/N interfaces on the overall performance of superstrate (pin-type) hydrogenated microcrystalline silicon (μc-Si:H) single-junction solar cells with wide band gap silicon oxide doped supporting layers is presented. By integrating the n-type a-Si:H materials with proper band gap and thickness values at the I/N interface, the band gap discontinuity between the μc-Si:H intrinsic and n-type nc-SiOx:H layers can be successfully compensated for, thereby improving the carrier collection, reducing the accumulation and recombination of photo-generated carriers near the I/N interface, and improving the overall current and power output of the μc-Si:H cells. Further adoption of an optimized hydrogen profiling technique based on the optimized n-type a-Si:H buffer layers yields an initial conversion efficiency of 10.05% for μc-Si:H single-junction solar cells with a thickness of 2 μm.