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 WS2 (semiconductor channel material) FETs have been used for this purpose. Through nanopatterning, 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 sub-threshold 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 WS2 (similar to 450- 480 nm) has also been observed, thereby demonstrating enhanced RGB detection.