Studies On The Properties Of P-CuSCN Thin Films Prepared By Electro- Deposition Method

CuSCN thin films were prepared by electrochemical deposition method in aqueous solutions using cupric sulphate and potassium thiocyanate as precursor materials. The effects of processing parameters on properties of thin films were studied and growth mechanism of film was discussed fundamentally. Process of the deposition was measured by voltammetry on potentiostat and the best condition of deposition was confirmed. The mixture of cupric sulphate aqueous solution and potassium thiocyanate aqueous solution is too instable to be used as electrolyte solution. Chelation mechanism, using ammonia, cetric acid and EDTA as chelated reagent, was used to obtain stable electrolyte solution. It is found that EDTA is the optimal chelated reagent and the solution with EDTA stayed for a few days is better for deposition.The linear sweep voltammetry is used to confirm the deposition potentials and test the process of deposition.Content of the SCN- in electrolyte solution, deposition potential and concentration of solution are important factors on quality of films. Morphology of the films deposited through the aquoues electrolyte solution with mol ratio Cu2+/SCN-=2:1 is best. Content of the SCN in film is increasing as the enhancement of content of the SCN- in solution. Single phase p-CuSCN thin films can be deposited on the potential range from 200mv to -500mv. It is difficult to deposited film when deposition potential is higher than 200mv. If deposition potential becomes too negative, e.g. below -600mv, Cu will be co-deposited out. The optimal potential is -500mv.The suitable concentration is between 0.01mol/L and 0.02mol/L.The deposition mechanism is based on the tunneling of electron transition and double electrical layer of interface between semiconductor and electrolyte.