Polycrystalline silicon thin-film solar cells on glass by aluminium-induced crystallisation and subsequent ion-assisted deposition (ALICIA)

A research project is under way at The University of New South Wales aiming at the realisation of a novel type of polycrystalline silicon thin-film solar cell on glass. The idea is to first create a thin large-grained polycrystalline seed layer on glass by aluminium-induced crystallisation of amorphous silicon and then to epitaxially thicken the seed layer with ion-assisted deposition. By mid-2003 this ALICIA project had achieved laboratory cells with voltages of up to 163 mV, as reported elsewhere. In the present paper we give an overview of recent progress (improved Si epitaxy process, improved control of base doping profile due to the use of phosphorus dopants instead of gallium, hydrogen passivation) that has improved the voltages of ALICIA solar cells to 270 mV Furthermore, the strategy for further voltage improvements is presented. At the present point in time only the voltages of ALICIA cells are known, but obviously solar cells also require current for good efficiency. Hence much improvement in both voltage and current is still needed. Copyright (C) 2004 John Wiley Sons, Ltd.