Enhanced optoelectronic and electrical characteristics in nanopatterned 2D dielectric (hBN)/ semiconductor (WS²) field effect transistors

We experimentally demonstrate improvement in electrical and optoelectronic properties of 2D material-based field effect transistor (FET) devices with the help of patterned 2D dielectric. Nanopatterned hexagonal boron nitride (hBN) (dielectric)/ p-type WS <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> (semiconductor channel material) FETs have been used for this purpose. Through nano-patterning, we have reduced the effective thickness of the gate dielectric (hBN), which improves the gate control of the transistor. This increases the on-off ratio and reduces the subthreshold swing of the transistor device. Due to light-trapping in our sub-wavelength nanopatterned hBN structure, photo response in the weak blue absorption wavelength regime of WS <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> (~ 450-480 nm) has also been observed, thereby demonstrating enhanced RGB detection.