Efficient Hydrogenated Amorphous Silicon Thin-Film Solar Cells Using Zinc Oxide Deposited by Atomic Layer Deposition as a Protective Interfacial Layer

Abstract

A single zinc oxide (ZnO) layer deposited by atomic layer deposition (ALD) was employed as a buffer layer on textured fluorine-doped tin oxide (FTO) glass in p-i-n-type hydrogenated amorphous silicon solar cells (a-Si:H SCs). ZnO was deposited between FTO glass and a p-type a-Si:H layer. The device with a 2 nm thick ZnO buffer layer deposition showed the highest cell efficiency as well as increased current density, showing considerable improvement in efficiency. This improvement was attributed to the protection against H2 plasma damage during plasma-enhanced chemical vapor deposition, which was confirmed by electrical impedance, conductivity, and optical transmittance measurements.