Comparative Study of MVHF and RF Deposited Large Area Multi-junction Solar Cells Incorporating Hydrogenated Nano-Crystalline Silicon

Abstract

AbstractWe report our investigations of large area multi-junction solar cells based on hydrogenated nano-crystalline silicon (nc-Si:H). We compared results from cells deposited by RF (13.56 MHz) at lower deposition rate (˜3 Å/s) and by Modified Very High Frequency (MVHF) at higher rate (≥ 10 Å/s). With optimized process conditions and cell structures, we have obtained ˜12% initial small active-area (˜0.25 cm2) efficiency for both RF and MVHF cells and 10˜11% large aperture-area (˜400 cm2) encapsulated MVHF cell efficiency for both a-Si:H/nc-Si:H double-junction and a-Si:H/nc-Si:H/nc-Si:H triple-junction structures on Ag/ZnO coated stainless steel substrate.