A thin-film solar cell of high-quality β-FeSi2/Si heterojunction prepared by sputtering

High-quality (110)/(101)-oriented epitaxial beta-FeSi2 films were fabricated on Si (111) substrate by the sputtering method. The critical feature was the formation of a high-quality thin beta-FeSi2 template buffer layer on Si (111) substrate at low temperature. It was demonstrated that the template is very important for the epitaxial growth of thick beta-FeSi2 films and for the blocking of Fe diffusion into the Si at the beta-FeSi2/Si interface. Hall effect measurements for beta-FeSi2 films showed n-type conductivity, with residual electron concentration around 2.0 x 10(17) cm(-3) and mobility of 50-400 cm(2)/V s. A prototype thin-film solar cell was fabricated by depositing n-beta-FeSi2 on p-Si (111). Under 100mW/cm(2) sunlight, an energy conversion efficiency of 3.7%, with an open-circuit voltage of 0.45V, a short-circuit current density of 14.8 mA/cm(2) and a fill factor of 0.55, was obtained. (c) 2005 Elsevier B.V. All rights reserved.