Very low temperature epitaxial growth n/sup +/ c-Si/p c-Si solar cells

Low temperature n-type silicon epitaxial growth was studied extensively as an alternative to the diffusion technology in n/sup +/p solar cells. It was confirmed by XTEM that epitaxial Si films could be grown at 100-300/spl deg/C. High open circuit voltages (Voc) and high efficiencies (Eeff) for n-type silicon epitaxial growth solar cells has been achieved on flat p-type (100) CZ-Si at very low temperature of less than 200/spl deg/C by standard plasma-enhanced chemical vapor deposition (PECVD). The combination of very thin c-Si layer grown at low hydrogen dilution under the low deposition pressure and thin c-Si layer grown at high hydrogen dilution under the higher deposition pressure was found to be effective as a good epitaxial emitter layers. The best Voc of 0.610 V and the best Eeff of 13.54% were obtained for homojunction solar cells having simple cell design (ITO/n/sup +/ c-Si/p c-Si/rear contact). Neither surface texturing nor back surface field is used.