Single WS2 Nanotube-Based Field Effect Transistor: Ambipolar Conduction and Self-Powered Photodetection

Semiconductive nanotubes offer the potential for miniaturized transistors with enhanced gate control through various configurations. In this work, we fabricated and electrically characterized a single WS2 nanotube-based field-effect transistor under both dark and white light illumination at ambient pressure and temperature. At drain voltages higher than 1 V, the device exhibits ambipolar conduction, with a hole mobility of 0.2 cm2V-1s-1 and an electron mobility of 0.13 cm2V-1s-1 at Vds=2V. The gate modulation has been extensively investigated, applying gate voltages up to 100 V. Furthermore, the WS2 nanotube-based device was evaluated as a photodetector, demonstrating light-induced modulation of the channel current via both gate and drain control. The single WS2 nanotube-based transistor also operates in self-powered mode, achieving a short-circuit current of 2.6 pA and an open-circuit voltage of approximately 3 mV. The electrical properties of this device show potential for complementary metal-oxide semiconductor (CMOS) applications, and contribute to the development of optoelectronic devices, including self-powered photodetectors.