A novel approach for improved passivation of a-Si and a-Si/c-Si surfaces from deuterium plasma effects

Abstract Amorphous silicon (a-Si) is essential for defect passivation and enhancing performance in high-efficiency heterojunction silicon solar cells (HJT). Deuterium plasma treatment (DPT) demonstrates superior resistance to light-induced defects and enhances the thermal stability of a-Si. This study investigates the effects of DPT applied at different stages—Pre, Post, and midway (Mid)—during plasma-enhanced chemical vapor deposition to optimize surface passivation and understand the underlying mechanisms. Both Mid and Post DPT achieved superior a-Si/c-Si passivation quality, significantly improving the minority carrier lifetime. For 10 nm a-Si passivation layers, the lifetimes reached 1889 μ s and 1049 μ s for the Mid and Post DPT, respectively, at an excess carrier density of 1.0 × 10 15 cm −3 . Thermal stability tests showed rapid degradation of a-Si passivation quality above 240 °C, with the lifetime dropping from 680 μ s to 493 μ s. In contrast, DPT-treated wafers demonstrated excellent thermal stability, with the lifetime reducing from 1025 μ s to 901 μ s under 1 sun calibration at 280 °C. These findings underscore the potential of DPT for enhancing passivation performance and thermal stability in HJT solar cells.