CuSCN Thin Film Deposited from Solutions at Room Temperature and its Optical Properties

CuSCN thin film was deposited on glass substrate from solutions at room temperature (20-25 degrees C) by the successive ionic layer adsorption and reaction (SILAR) method. The crystalline structure, morphology, and optical properties of obtained film were characterized by X-ray diffraction, scanning electron microscope, and optical transmittance. The key parameters influencing the deposition of CuSCN on substrate were discussed briefly. The CuSCN film exhibits obvious crystallinity, preferential orientation along c-axis, and dense and uniform morphology. Two classes of CuSCN particles are observed, the larger particles in size of 50-100nm and the smaller ones in size of 20-30nm. The transmittance of the film at the band of 400-800nm is 50%-70%, and the optical band gap is estimated to be 3.94eV. Mechanism analysis indicates that the growth of CuSCN film is affected significantly by three factors, namely, the molar ratio of S2O32- to Cu2+ in the copper precursor, the substrate rinsing mode, and the growth temperature. The relatively high concentration. of complex ions, the substrate-rinsing after multiple reaction cycles, and the room-temperature deposition are beneficial to the growth of high quality CuSCN film.