Intrinsic/doped stacked hydrogenated amorphous silicon (a-Si:H) are widely used passivation layers for amorphous/crystalline silicon (a-Si/c-Si) heterojunction solar cells. This work reports that hot wire chemical vapor deposition of doped a-Si:H can significantly modify the property of the underlying intrinsic a-Si:H (a-Si:H(i)) as well as a-Si/c-Si interface passivation, which stems from the in-diffusion of highly reactive atomic hydrogen. Fourier transform infrared spectroscopy, spectroscopic ellipsometry and Raman analyses indicate that the underlying a-Si:H(i) films become more compact and less defected as a result of network reconstruction during doped a-Si:H capping. After this reconstruction, underdense a-Si:H(i) films obtained superior passivation quality than widely used dense layers, despite the inferior quality in the initial state. Effective minority carrier lifetime of c-Si passivated by underdense a-Si:H(i) was 19.9 ms, much higher than 15.2 ms in the case of using dense a-Si:H(i). The porous structure of underdense a-Si:H(i) facilitates hydrogen diffusion towards a-Si/c-Si interface and hence a rapid reduction of interface defect densities occurs, accounting for the better passivation quality. SHJ solar cells (160 μm, 156 × 156 mm) with industry-compatible process were fabricated, yielding the efficiency up to 23.0% with high V values of 741 mV.
|Original language||English (US)|
|Number of pages||6|
|Journal||Applied Surface Science|
|State||Published - Dec 26 2018|
Bibliographical noteKAUST Repository Item: Exported on 2021-02-19
Acknowledgements: The authors gratefully acknowledge ULVAC for their equipment support of HWCVD deposition system. This work was supported by projects of the Strategic Priority Research Program and the Joint Fund of Chinese Academy of Sciences (XDA17020403, 6141A01141604), and a project of Shanghai Municipal Science and Technology Committee (17DZ1201100).