Microcrystalline Silicon Carbide p-Layer with Wide-Bandgap and Its Application to Single- and Triple-Junction Silicon Thin-Film Solar Cells

Abstract

Wide-bandgap, high-quality p-type microcrystalline silicon carbide (p-µc-SiC) films have been prepared by radio frequency plasma-enhanced chemical vapor deposition (RF-PECVD) technique for use as window layers for single- and triple-junction thin-film silicon solar cells. We have found that the p-µc-SiC films have wider optical bandgaps and lower absorption spectra in the short-wavelength region than the conventional p-µc-Si films. The new p-type doping layer was applied as a window layer of a microcrystalline silicon (µc-Si:H) single-junction cell, and the thin-film solar cell with the new window layer showed higher open circuit voltage (Voc) and conversion efficiency. In addition, the insertion of an optimized p/i buffer layer was essential for reducing atomic damage at the p/i interface and obtaining a higher conversion efficiency. The optimized p-µc-SiC layer and p/i buffer layer were adopted successfully as a new window layer for the bottom cell within the triple-junction cell structure.