Electrolytically deposited Cadmium Selenide Films for Photovoltaic Applications

Abstract

Abstract. CdSe films were electrodeposited on pure nickel substrates. The nickel substrate was polished to a mirror finish by Al 2 O 3 paste, etched in 10% HCl solution for 40 s and rinsed thoroughly by de-ionized water. The deposition bath contained solutions with excessive Cd 2+ (0.2M) from CdSO 4 and small amounts of SeO 2 (1x10 -3 M). The pH of the bath was adjusted to a value of 2.2 at RT by adding 10% H 2 SO 4 . The bath was first thermostated at the required temperature, which varied from 55°C to 65°C. Plating was accomplished at deposition potential 1000 mV (vs. Hg/Hg 2 SO 4 ). The films formed had a uniform thickness and it was found to be approximately 2.0 µm thick (for 20 min electrodeposition process. The produced CdSe films were characterized by X-Ray diffraction and SEM. The induced semiconductor doping effect by thermal annealing in pure dry nitrogen gas was also investigated. Gold contacts were placed on top of the CdSe films, either by evaporation, or mechanically. Depending on the deposition parameters the electrical characteristics of the Ni/CdSe/Au structures may exhibit rectification properties. The optical excitation of the structure was investigated for various CdSe thicknesses.

Synthesis and Characterization of Cadmium Selenide Thin Films by Vacuum Deposition Technique

“…A direct band gap range of CdSe is between 1.65 eV to 1.84 eV [2,4]. Cadmium Selenide (CdSe) is a solid binary compound of cadmium and selenium which have different crystal structures like hexagonal (wurtzite), cubic (zinc blende) and cubic rock-salt [3,8]. Because of the low production cost of CdSe thin films, the use of polycrystalline semiconducting thin film has attracted much interest in various electric and optoelectronic devices in the last decade [5].…”