Ambipolar conduction in gated tungsten disulphide nanotube

Abstract

Devices based on transition metal dichalcogenide nanotubes hold great potential for electronic and optoelectronic applications. Herein, the electrical transport and photoresponse characteristics of a back-gate device with a channel made of a single tungsten disulfide (WS₂) nanotube are investigated as functions of electric stress, ambient pressure, and illumination. As a transistor, the device exhibits p-type conduction, which can be transformed into ambipolar conduction at a high drain–source voltage. Increasing ambient pressure enhances the p-type behaviour, while exposure to light has the opposite effect, enhancing n-type conduction. The ability to operate the device as either a p-type or n-type transistor makes it promising for complementary metal–oxide–semiconductor (CMOS) circuit applications. Light enhances the conductivity, allowing for further control and enabling the device to function as a photodetector with a photoresponsivity of about 50 mA W⁻¹ and a broadband response in the visible range. The combination of voltage, pressure and light control paves the way for using the WS₂ nanotube transistor as a multifunctional device.