Influence of ZnSnO_x barrier layer on the texturing of ZnO:Al layers for light management in flexible thin-film silicon solar cells

摘要

Transparent polymer films such as polyethylene terephthalate (PET) present a cost efficient substrate material for flexible solar cells. In addition to certain process temperature limitations, these materials are permeable to moisture and/or oxygen, and additional barrier layers are required to prevent the diffusion of contaminating atoms into the photovoltaic device. In this study, the influence of a ZnSnO_x barrier layer deposited on PET substrates on the properties of the subsequently grown low temperature (<140 °C) aluminum-doped zinc oxide (ZnO:Al) layers is examined. We investigate the electrical and optical properties, as well as surface topography of ZnO:Al layers grown on PET and PET/ZnSnO_x substrates before and after wet-chemical etching treatment, needed to maintain the advanced light management schemes in solar cells. A-Si:H solar cells show an improvement in all photovoltaic parameters when ZnSnO_x barrier layers are applied on PET substrates, leading to a remarkable increase in efficiency from 4.8 to 6.9%.