High-performance lateral MoS2-MoO3 heterojunction phototransistor enabled by in-situ chemical-oxidation

Abstract

Construction of in-plane p-n junction with clear interface by using homogenous materials is an important issue in two-dimensional transistors, which have great potential in the applications of next-generation integrated circuit and optoelectronic devices. Hence, a controlled and facile method to achieve p-n interface is desired. Molybdenum sulfide (MoS2) has shown promising potential as an atomic-layer n-type semiconductor in electronics and optoelectronics. Here, we developed a facile and reliable approach to in-situ transform n-type MoS2 into p-type MoO3 to form lateral p-n junction via a KI/I2 solution-based chemical oxidization process. The lateral MoS2/MoO3 p-n junction exhibits a highly efficient photoresponse and ideal rectifying behavior, with a maximum external quantum efficiency of ∼650%, ∼3.6 mA W−1 at 0 V, and a light switching ratio of ∼102. The importance of the built in p-n junction with such a high performance is further confirmed by high resolution photo current mapping. Due to the high photoresponse at low source-drain voltage (VDS) and gate voltage (VG), the formed MoS2/MoO3 junction p-n diode shows potential applications in low-power operating photodevices and logic circuits. Our findings highlight the prospects of the local transformation of carrier type for high-performance MoS2-based electronics, optoelectronics and CMOS logic circuits.