Development of the Passivation Layer For P-type CuI Thin Film Fabricated by the 2-step Method as the Novel Hole Selective Contact of Silicon Heterojunction Solar Cells

Abstract

The passivation of the heterojunction interfaces between the carrier selective contact and the crystalline silicon (cSi) is crucial to achieve high power conversion efficiency in the silicon heterojunction solar cells. We develop a passivation layer applicable to the hole selective contact copper iodide (CuI) fabricated by the 2-step method which includes direct deposition of copper (Cu) on the substrate. The intrinsic hydrogenated amorphous silicon (i-a-Si:H) layer and theintrinsic hydrogenated amorphous silicon oxide (i-a-$\mathrm{SiO}_{\mathbf {x}}$:H) layer are stacked on c-Si substrate by the plasma enhanced chemical vapor deposition (PECVD) before CuI fabrication. We demonstrate that the i-a-$\mathrm{SiO}_{\mathbf {x}}$:H layer prevents Cu from diffusing into the i-a-Si:H layer and degrading the minority carrier lifetime of the substrate.