Effect of high crystalline p /i interface layer on the performance of microcrystalline silicon solar cells deposited in a single‐chamber system

Abstract

AbstractWe studied boron (B) contaminations at the p /i interface in hydrogenated microcrystalline silicon (μc‐Si:H) p ‐i ‐n solar cells deposited in a single chamber system. We used secondary ion mass spectroscopy to measure B depth profiles in μc‐Si:H thin films with different crystalline volume fraction (Xc) and found that μc‐Si:H films with a higher Xc showed a less boron contamination than that with a lower Xc in the amorphous/microcrystalline transition region. Based on this result, we proposed an interface layer with a suitable high Xc inserted between p and i layers to reduce the contaminations and then improve the performance of μc‐Si:H solar cells prepared in the single‐chamber system. The solar cell experiments indeed showed that a suitable high Xc interface layer decreased the boron contaminations at the p /i interface. The solar cell efficiency was increased with an enhanced short wavelength response. Combined with the optimized high Xc interface layer, the high quality μc‐Si:H, and the light trapping effect of front electrode, a single‐junction μc‐Si:H solar cell with 6.3% (1.0 cm2) of conversion efficiency was made in the single‐chamber system. Using the improved μc‐Si:H solar cell as the bottom cell, we achieved a 10.05% (1.0 cm2) efficiency for an a‐Si:H/μc‐Si:H tandem solar cell (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)