Lateral WSe_2 p–n Junction Device Electrically Controlled by a Single-Gate Electrode

摘要

Semiconductor p-n junctions are building blocks for optoelectronic devices. Recently, p-n junction devices based on 2D transition metal dichalcogenides (TMDCs) have been demonstrated in optoelectronic applications due to their thin thickness, flexibility, high carrier mobility, and high light-absorption properties. To fabricate 2D semiconductor p-n junction devices, various methods are demonstrated, such as heterojunction structures, chemical doping, and electrostatic doping. In this work, lateral both p-n and n-p junctions in WSe2 devices, electrically controlled by using only a single-gate electrode, are first reported. It is demonstrated that the single-gated WSe2 p-n and n-p diodes form an internal built-in electrical field, showing strong diode-like current rectifying behavior and photovoltaic effect under the illumination. The resultant device exhibits a high current rectification ratio up to approximate to 10(6) and a power conversion efficiency of 0.1% under AM 1.5 illumination. A logical inverter based on the lateral and in-plane contacted WSe2 device with a hexagonal boron nitride (h-BN) gate dielectric is also presented. The electrode architecture engineering based on a single TMDC will be useful for applications that are more complicated such as p-n junction optoelectronic devices and inverters.