Preparation Of Znse Thin Film By Electro-Deposition

The zinc selenide is aⅡ-Ⅵcompound semiconductor with a direct bandgap of 2.7 eV, which has been widely studied because of its potential use in semiconductor devices and as a window material for solar cells, especially by CVD, MBE and HWE.The electrodeposition has been found to be a very good method to fabricate thin polycrystalline films of compound semiconductors for using in photovoltaic solar cells.In this investigation, the formation of ZnSe has been accomplished in an aqueous bath(pH=2.3) during electrochemical reduction of an electrolyte containing SeO2(0.001～0.008M) and ZnSO4 (0.1～0.8M) on an indium tin oxide glas.The potentiostatic method is chosen to control the stoichiometry.The influence of growth conditions such as deposition potential, pH, deposition temperature and concentration of constituents of the solution and composition are investigated.We have shown that in order to get the Zn/Se ratio close to 1 in the film, the solution should contain a higher concentration of the precursor, Zn (0.2M), of the less noble constituent of the compound and a very low concentration of the precursor, SeO2 (0.001 M) of the nobler one, the pH is aboat 2.3, the deposited potential is -800mV.and the deposited time is 20min.