Investigation of Nickel Oxide as Carrier-selective Interlayer for Silicon Solar Cell Contacts

Thin film crystalline silicon (c-Si) solar cells have been a potential candidate to reduce the capital expenditure associated with traditional silicon photovoltaic market. This paper presents the sputtered NiO$_{\mathbf {x}}$ to be a potential candidate as hole-selective layer for c-Si solar cell contacts. NiO$_{\mathbf {x}}$ has a very small valence band offset (VBO $) ( \sim 0.1$ eV) and a large conduction band offset (CBO) with Si $( \sim 2$ eV), which makes it a promising candidate for hole-selective interlayer materials to reduce the contact recombination. In this paper, the effect of annealing condition on the NiO$_{\mathbf {x}}$/Si interface quality is first evaluated by Hall resistivity measurement. Also, the transport of both majority and minority carriers due to NiO$_{\mathbf {x}}$/Si band alignment is investigated by transmission line measurement. Results in this paper show that the sputtered NiO$_{\mathbf {x}}$ can be an effective interlayer material for thin film c-Si solar cell contacts.