Photovoltaic Properties of Monolayer 2D Lateral Heterojunction Devices

Abstract

The recent development of two-dimensional (2D) monolayer lateral semiconductor has created new paradigm to develop p-n heterojunctions, the building block of electronic devices. Albeit, the growth methods of these heterostructures typically result in alloy structures at the interface, limiting the development for high efficiency photovoltaic (PV) devices. Here, we explore the PV properties of sequentially-grown alloy-free 2D monolayer WSe2-MoS2 lateral p-n heterojunction. Our PV devices show extraordinary power conversion efficiencies of 1.07. Moreover, the large surface active area of our PV devices enables the full exposure of the depletion region, leading to excellent omnidirectional light harvesting characteristic with only 10% reduction of efficiency at incident angles up to 75°—unachievable by conventional vertical solar cells. Modeling studies also demonstrate the PV devices comply with typical principles, greatly increasing the feasibility for further development. Furthermore, our appropriate electrode-spacing design led to environment-independent PV properties. These robust PV properties deriving from the atomically-sharp lateral p-n interface can help develop next-generation 2D monolayer-based electronic devices.