Near Unity Absorbance and Photovoltaic Properties of TMDC/Gold Heterojunction for Solar Cell Application

Abstract

In this paper, near unity broadband absorption of Van der Waals semiconductors on a metallic substrate, and their photovoltaic performances in the visible spectrum are simulated. Ultrathin layered semiconductors such as Molybdenum disulfide (MoS2), Tungsten disulfide (WS2), Molybdenum di-selenide (MoSe2), Tungsten di-selenide (WSe2), Molybdenum ditelluride (MoTe2), and Tungsten ditelluride (WTe2) can create strong interference by damping optical mode in their multilayer form and increase light absorption at their heterojunctions with noble metals. From our simulation, it is observed that this absorbance can reach up to 94% when the semiconductors are placed on a gold substrate. The optimum thickness of these semiconductors in their heterostructures with gold is analyzed to create resonant absorption to generate the maximum amount of current density. The power conversion efficiency of the designed Schottky junction solar cells is calculated from their current density vs bias voltage characteristics that ranges from 1.57% to 6.80%. Moreover, the absorption coefficient, dark current characteristic, electric field intensity distribution in the device, and carrier generation rate during light illumination are presented with a view to characterizing and comparing among the parameters of TMDC based nanoscale solar cell.