Improving the Interface Passivation of Si HJ Solar Cells by Interrupted Deposition of Thin a-Si:H Film

In this paper, the effects of interrupted deposition of intrinsic hydrogenated amorphous silicon (i.a-Si:H) on the Si surface passivation are studied. Vibrational and optical properties of the i.a-Si:H films have been studied using Fourier transform infrared (FTIR) and Variable angle spectroscopic ellipsometry (VASE) respectively. The experiment confirms that the improved passivation from interrupted deposition arises from film densification and pinhole filling during the two-step deposition process. The i.a-Si:H films with interrupted deposition showed a higher fraction of low Si-H stretching mode vibration than the uninterrupted growth – an indication of compactness and densification, by incorporation of free hydrogen atoms into the i.a-Si:H network and resulting in improved implied open circuit voltage, iV OC >750mV with effective minority carrier lifetime, τeff > 5 ms.