Near-infrared photodetector performance of Cu<inf>2</inf>ZnSnS<inf>4</inf> in the metal-semiconductor-metal configuration: Theoretical studies

Cu2ZnSnS4 (CZTS), an earth-abundant, nontoxic quaternary semiconductor material, is investigated with the possibility of it as a near-infrared MSM (metal-semiconductor-metal) photodetector. The metal-semiconductor-metal (MSM) device configuration, i.e., Au/CZTS/FTO, is probed numerically using one-dimensional macroscopic simulations to understand the detector response. The impacts of various CZTS absorber parameters such as thickness, doping concentration, and bulk defects are examined to achieve the minimum dark current and the maximum photocurrent for the optimized photodetector response. We observed that the simulated Au/CZTS/FTO device is suitable for the 750 nm wavelength region, showing 0.5 A W−1 responsivity and a very large photo to dark current ratio (~ 1012 or more) for a one μm thick CZTS absorber layer.