Abstract
Graphene, as a two-dimensional carbon material, has shown superior material properties including high optical transmittance, excellent mechanical flexibility, low resistivity, and high carrier mobility. Theoretically, a Schottky junction can be formed by depositing graphene onto the surface of a moderately n-doped semiconductor. Thus, graphene is expected to have great potential in the field of photovoltaics. In this study, the feasibility of graphene/Si and graphene/GaAs Schottky junction solar cells was investigated. For the former, graphene was transferred directly onto n-type Si substrates of different doping concentrations. We found that for the Si substrate doped in the order of 10^15 cm^-3, the graphene/Si junction exhibited a well rectified behavior, and the resulting solar cell showed a maximum efficiency of 1.55 %. For the type of graphene/GaAs junction solar cells, graphene was transferred directly onto the GaAs films grown by MBE on highly n-doped GaAs substrates. The effects of GaAs doping concentration and growth time on the performance of the cells were investigated. These junction solar cells showed a maximum efficiency of 0.143%.