Performance-Tunable MoS2 Homojunction Photodiode Based on Different Built-In Electric Field

In traditional silicon-based semiconductor manufacturing, diodes with rectifier function are the basis of various electronic devices, and it can be typically achieved through a doping process with ion implantation of the group III–V elements. However, for 2-D semiconductors, such as MoS2, the ultrathin thickness of their channel layer makes it challenging to employ ion implantation techniques for the fabrication of diodes. Here, we fabricated a performance-tunable MoS2 homojunction photodiode without the need for external element doping process. By applying different gate voltages, the built-in electric field at the homo-interface can be adjusted, endowing the device with p-n-junction-like characteristics, thereby achieving a tunable rectification ratio (RR) (from $10^{{3}}$ to 2). In addition, outstanding photovoltaic effect is achieved at a wavelength of 532 nm, including a high responsivity of up to 191 mA/W and a high-specific detectivity of up to approximately $4.5\times 10^{{10}}$ Jones. This research is of significant importance in the field of 2-D optoelectronic devices, providing new design ideas and fabrication methods for high-performance 2-D photodiodes.