a-SiOx:H passivation layers for Cz-Si wafer deposited by hot wire chemical vapor deposition

Abstract In order to get the high photoelectric conversion efficiency a -Si:H/ c -Si solar cells, high quality intrinsic hydrogenated passivation layer between the a -Si:H emitter layer and the c -Si wafer is necessary. In this work, hot wire chemical vapor deposition (HWCVD) is used to deposite intrinsic oxygen-doped hydrogenated amorphous silicon ( a -SiO x :H) and hydrogenated amorphous silicon ( a -Si:H) films as the intrinsic passivation layer for a -Si:H/c-Si solar cells. The passivation effect of the films on the c -Si surface is shown by the effective lifetime of the samples that bifacial covered by the films with same deposition parameters, tested by QSSPC method. The imaginary part of dielectric constant ( e 2 ) and bonds structure of the layers are analyzed by Spectroscopic Ellipsometry(SE) and Fourier Transfom Infrared Spectroscopy(FTIR). It is concluded that: (1) HWCVD method can be used to make a -SiO x :H films as the passivation layer for a -Si:H/c-Si cells and the oxidation of the filament can be overcome by optimizing the deposition parameters. In our experiments, the lowest surface recombination velocity of the c -Si wafer is 3.0 cm/s after a -SiO x :H films passivation. (2) Oxygen-doping in the amorphous silicon layers can increase H content and the band-gap of films, similar as the phenomenon of the films deposited by PECVD.