Highly Oriented Crystalline Silicon Film for Photovoltaic Cells

Stanford researchers have patented a low cost, textured crystalline silicon (c-Si) photovoltaic film fabricated via scalable, ion beam assisted deposition (IBAD) on display glass. Crystalline silicon (c-Si) is a nearly ideal photovoltaic (PV) material, but expensive and energy intensive silicon wafer fabrication makes up nearly half the cost of a typical photovoltaic module. In order to reduce PV cost, the inventors used a template seed layer of calcium fluoride (which has a close lattice match with silicon) to grow biaxially textured heteroepitaxial c-Si on glass, a low cost substrate. This process method controls the grain boundary alignment to improve microelectronic efficiency and performance. IBAD is a well-established, room-temperature technique that is amenable to a variety of substrates and process scaling. This technology could be used to coat large area and long length substrates with high performance c-Si to help achieve low-cost solar cells.