Characterization of Defects-Location in Hydrogenated Microcrystalline Silicon Thin Films and Its Influence on Solar Cell Performance

Abstract

Hydrogenated microcrystalline silicon (µc-Si:H) thin films were prepared by hot-wire chemical vapor deposition (HW-CVD). Large grains containing nano-sized crystallites observed by scanning electron microscopy (SEM). The change in defect density in the absorbers of experimentally-prepared solar cells as a function of crystalline volume fraction was estimated from a comparison of simulated results using an AMPS-1D device simulator and previously reported solar cell performance. The modeled structure of grains in µc-Si:H thin films which was built based on the observed results was combined with the estimated defect density in the i-layer. The combination showed that the change in defect density in the i-layer of a solar cell could be explained well by employing the assumption that the defects exist at boundaries between the large grains, not between the nano-sized crystallites.