Orientation growth and electrical property of CuSCN films associated with the surface states

Highly oriented CuSCN films were prepared through an aqueous electrochemical method. Crystallographic orientation of the film was successfully tuned from a direction with the (101) plane parallel to the substrate to another direction with the (001) plane parallel to the substrate simply by adjusting solution conditions. The formation mechanisms associated with the surface states were discussed based on the crystal structure of a rhombohedral form of CuSCN and the coordination chemistry. The Mott-Schottky measurements demonstrated that the flat-band potential of the CuSCN film was related to the crystallization orientation and the surface atom arrangement. The hole concentration of the CuSCN film varied with the amount of SCN- ions suggesting that the present electrochemical process is a facile route for modifying the p-type conductivity.