HEXAGONAL CADMIUM CHALCOGENIDE THIN-FILMS PREPARED BY ELECTRODEPOSITION FROM NEAR-BOILING AQUEOUS-SOLUTIONS

Thin, n-type, CdSe and CdSexTe1-x semiconductive films were prepared b y cathodic electrodeposition onto titanium electrodes. An electrochemi cal cell was specially designed in order to perform electrodeposition in a near-boiling aqueous-ethyleneglycol bath at a temperature of appr oximately 110 degrees C. The composition of the as-grown films, their crystal structure, morphology and band-gap width were studied as a fun ction of the deposition potential and chalcogen ion concentration. It is shown that high temperatures have a positive effect on the crystal quality and the photoresponse stability of cadmium chalcogenide thin f ilms even by employing electrolytes rather concentrated in selenous ac id. Under specific conditions, a small shift in deposition potential b rings about a complete phase transformation of the CdSe layers. In thi s manner, the described method enables the preparation of hexagonal Cd Se deposits.