This paper introduces Ta-doped MoSe2 via substitutional doping. The transfer characteristic of the synthesized MoSe2 can be controllably switched from n-type to ambipolar, and to p-type. Based on the Ta-doped MoSe2, outstanding homojunction photodetectors (high external quantum efficiency ≈42% and fast response speed ≈20 µs) and inverters (high voltage gain ≈34) are demonstrated. Abstract 2D materials, of which the carrier type and concentration are easily tuned, show tremendous superiority in electronic and optoelectronic applications. However, the achievements are still quite far away from practical applications. Much more effort should be made to further improve their performance. Here, p-type MoSe2 is successfully achieved via substitutional doping of Ta atoms, which is confirmed experimentally and theoretically, and outstanding homojunction photodetectors and inverters are fabricated. MoSe2 p–n homojunction device with a low reverse current (300 pA) exhibits a high rectification ratio (104). The analysis of dark current reveals the domination of the Shockley–Read–Hall (SRH) and band-to-band tunneling (BTB) current. The homojunction photodetector exhibits a large open-circuit voltage (0.68 V) and short-circuit currents (1 µA), which is suitable for micro-solar cells. Furthermore, it possesses outstanding responsivity (0.28 A W−1), large external quantum efficiency (42%), and a high signal-to-noise ratio (≈107). Benefiting from the continuous energy band of homojunction, the response speed reaches up to 20 µs. Besides, the Ta-doped MoSe2 inverter exhibits a high voltage gain (34) and low power consumption (127 nW). This work lays a foundation for the practical application of 2D material devices.
Published in: "Small".