Multicrystalline silicon solar cells exceeding 20% efficiency

This paper presents the first conversion efficiency above 20% for a multicrystalline silicon solar cell. The application of wet oxidation for rear surface passivation significantly reduces the process temperature and therefore prevents the degradation of minority-carrier lifetime. The excellent optical properties of the dielectrically passivated rear surface in combination with a plasma textured front surface result in a superior light trapping and allow the use of substrates below 100 mum thickness. A simplified process scheme with laser-fired rear contacts leads to conversion efficiencies of 20.3% for multicrystalline and 21.2% for monocrystalline silicon solar cells on small device areas (1cm(2)). Copyright (C) 2004 John Wiley Sons, Ltd.