Single $\text{WS}_{2}$ 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 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{W S}_{\text{2}}$</tex> 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 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$0.2 ~\text{cm}^{2} ~\mathrm{V}^{-1} ~\mathrm{s}^{-1}$</tex> and an electron mobility of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$0.13 ~\text{cm}^{2} \mathrm{V}^{-1} ~\mathrm{s}^{-1}$</tex> at <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{V}_{\text{ds}}=2 ~\mathrm{V}$</tex>. The gate modulation has been extensively investigated, applying gate voltages up to 100 V. Furthermore, the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{W S}_{\text{2}}$</tex> nanotube-based device was evaluated as a photodetector, demonstrating light-induced modulation of the channel current via both gate and drain control. The single <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{W S}_{\text{2}}$</tex> nanotube-based transistor also operates in self-powered mode, achieving a short-circuit current of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{2. 6 ~ p A}$</tex> 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.