Preparation and characterization of vanadium-implanted silicon for intermediate band solar cell applications

Abstract

The research of intermediate band solar cells has become a hot spot in the field of photovoltaics. The preparation of intermediate band materials is a key for intermediate band solar cell applications. In this paper, we attempted to prepare the intermediate band photovoltaic materials with supersaturated vanadium-doped silicon by ion implantation and rapid thermal treatment (RTP). The results show that the RTP technique can recover the damage to the lattice and morphology caused by ion implantation and can promote carrier activation and mobility. Moreover, the near infrared absorption of the samples is significantly enhanced, which indicates that some subband absorptions have been implemented in the samples. Furthermore, the minority carrier lifetime increases with increasing the dose of vanadium ion. This agrees with the intermediate-band prediction, suggesting an intermediate band is formed in the vanadium-doped silicon. In addition, the Arrhenius analysis shows that the intermediate band is located at about 0.43 eV below the conduction band edge of silicon. Our results indicated that the IB photovoltaic materials can be effectively prepared by vanadium-implantation in silicon and RTP technique.