Stability of graphene–silicon heterostructure solar cells (Phys. Status Solidi A 4∕2014)
V. V. Brus, M. A. Gluba, X. Zhang, K. Hinrichs, J. Rappich and N. H. Nickel
Version of Record online: 4 APR 2014 | DOI: 10.1002/pssa.201470223
Graphene has become an extremely prospective material for numerous applications because of its excellent electrical and optical properties. The combination of conductivity and high transparency and the ability of large-area production render graphene suitable as a contact layer and transparent electrode in solar cells. Graphene brought into direct contact with n-type silicon introduces a built-in electric field at the heterojunction interface and forms a Schottky contact. Solar cells utilizing this effect show a conversion efficiency of 4.2%. However, the graphene-Si Schottky diodes are not stable and degrade strongly during the first days. In the study by Brus et al. (pp. 843–847) the influence of the graphene-silicon interface on the solar cell properties is investigated. The quality of this interface is crucial since the concentration of localized states and its ability to block minority carriers influence the device performance significantly. Passivation of the silicon surface with methyl groups prior to graphene deposition reduces recombination loss at the graphene/Si heterojunction. In addition, it enhances and stabilizes the photoelectric performance of undoped graphene/n-type c-Si(111) solar cells.