High-performance humidity sensor constructed with vertically aligned graphene arrays on silicon Schottky junctions

Vertically aligned graphene arrays (VAGAs) are perpendicularly oriented and interconnected by arrangements with high aspect ratios and specific surface areas, promoting the gas molecule adsorption capacity and active surface sensitivity. By taking advantage of plasma-assisted chemical vapor deposition (PACVD), growth of VAGAs on silicon (Si) substrate has been demonstrated. As-grown VAGAs/Si has excellent Schottky junction-based humidity sensing characteristics with fast response and recovery time. Joule-heating dismisses physical absorbed vapor molecules from the vertical arrangement, realizing fully-reversible operation. The mechanism of humidity detection is explored by the scanning Kelvin probe microscopy (SKPM) and finite difference time domain (FDTD) simulation. Our study may promote the advancement of gas sensors.