Efficient hydrogenated amorphous silicon thin-film solar cells using zinc oxide deposited by atomic layer deposition as a protective interfacial layer

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 H ₂ plasma damage during plasma-enhanced chemical vapor deposition, which was confirmed by electrical impedance, conductivity, and optical transmittance measurements.