Ultra-thin g-C3N4 nanosheets wrapped silicon nanowire array for improved chemical stability and enhanced photoresponse

In order to inhibit the oxidation of Si materials in aqueous solution, Si nanowire array was wrapped by ultra-thin g-C3N4 nanosheets via an electrophoresis process. Scanning electron microscopy and transmission electron microscopy images showed that g-C3N4 nanosheets were evenly distributed on the surface of Si nanowire array. X-ray diffraction patterns indicated that Si nanowire array/g-C3N4 nanosheets were composed of Si (4 0 0 crystal plane) and g-C3N4 (0 0 2 and 1 0 0 crystal planes). The cyclic voltammetry curves revealed that the corrosion of Si nanowire array was restrained under the protection of g-C3N4 nanosheets. Furthermore, the photocurrent density of Si nanowire array/g-C3N4 nanosheets increased by nearly 3 times compared to that of bare Si nanowire array due to the effective charge separation caused by the built-in electric field at the interface. This work will facilitate the applications of Si materials in aqueous solution, such as solar energy harvest and photocatalytic pollution control.