Impact of bilayer structures on the surface passivation quality of high‐rate‐sputtered hydrogenated amorphous silicon for silicon heterojunction solar cells

Abstract

AbstractCrystalline silicon surface passivation effect of intrinsic hydrogenated amorphous silicon (i‐a‐Si:H) films deposited by radio‐frequency facing target sputtering (RF‐FTS) using a two‐step deposition technique was investigated. In the two‐step deposition technique, an i‐a‐Si:H layer was deposited at a high sputtering power condition after the deposition of i‐a‐Si:H at a low sputtering power condition. The two‐step deposition technique drastically improved the passivation quality of i‐a‐Si:H compared with a conventional single‐step deposition technique. Only 0.5‐nm‐thick i‐a‐Si:H deposited at a low sputtering power suppresses the initial sputtering damage to the crystalline silicon surface. A high average deposition rate of 14.1 nm/min was also achieved. A non‐textured silicon heterojunction solar cell using an i‐a‐Si:H passivation layer deposited by the two‐step method shows a conversion efficiency of 17.4% (Voc = 0.679 V, Jsc = 35.0 mA/cm2, FF = 0.732).