Interface designed MoS(2)/GaAs heterostructure solar cell with sandwich stacked hexagonal boron nitride

MoS(2) is a layered two-dimensional semiconductor with a direct band gap of 1.8 eV. The MoS(2)/bulk semiconductor system offers a new platform for solar cell device design. Different from the conventional bulk p-n junctions, in the MoS(2)/bulk semiconductor heterostructure, static charge transfer shifts the Fermi level of MoS(2) toward that of bulk semiconductor, lowering the barrier height of the formed junction. Herein, we introduce hexagonal boron nitride (h-BN) into MoS(2)/GaAs heterostructure to suppress the static charge transfer, and the obtained MoS(2)/h-BN/GaAs solar cell exhibits an improved power conversion efficiency of 5.42%. More importantly, the sandwiched h-BN makes the Fermi level tuning of MoS(2) more effective. By employing chemical doping and electrical gating into the solar cell device, PCE of 9.03% is achieved, which is the highest among all the reported monolayer transition metal dichalcogenide based solar cells.