Gate tunable photovoltaic effect in a MoSe2 homojunction enabled with different thicknesses

Abstract

Two-dimensional (2D) material based photovoltaic devices have attracted attention due to their atomically thin profile, strong light–matter interaction and mechanical flexibility. van der Waals heterojunctions, assembled with different 2D materials and a homojunction, are achieved with a doping technique and have been demonstrated to have considerable photovoltaic properties. Here, a more facile approach is proposed to realise an in-plane MoSe₂ homojunction with a gate tunable and highly efficient photovoltaic effect. By applying a negative back gate, the device can exhibit a current rectification ratio as high as 10⁵ and a significant V_oc of 0.24 V under illumination. The high power conversion efficiency of 1.9% and high photo-responsivity of 550 A W⁻¹ with a fast temporal response of 10 ms indicate that our MoSe₂ homojunction based device is a promising candidate in photovoltaic and photodetection applications.