Optical and Structural Properties of Copper Doped CdS Thin Films Prepared by Pulsed Laser Deposition
نویسندگان
1 Department of Physics,Sharif University of Technology
2 Department of Physics,Sharif University of Technology
doi
چکیده
This paper presents the study of the structural and optical properties of copper doped cadmium sulde thin lms prepared by pulsed Nd:YAG laser. The copper concentration in the targets was varied from 0.05% to 5% in weight and they were heated at a temperature of 500C in air for one hour. It was observed that annealing un-doped and doped thin lms at temperatures above 160C leads to an abrupt increase in the optical transmission, changing from dark brownish to transparent yellowish. For annealed samples at 300C, increasing Cu concentration from 0.0% to 2%, leads to an increase in the optical transmission up to 80%, at a wavelength of about 700 nm. XRD patterns showed the hexagonal phase of cadmium sulde and a number of CdO peaks relating to the partial oxidation of cadmium. The XPS spectra of the annealed samples indicate an accumulation of Cu at the surface. Therefore, Cu impurity can enhance CdS oxidation and the size of the crystallites. The highest value of the photo-current for the samples is related to the lowest Cu concentration, i.e: 0.05%.