THE EFFECT OF CHEMICAL TREATMENT ON THE CdS FILMS PREPARED BY CLOSED SPACE SUBLIMATION (CSS) METHOD

Abstract

CdS films have been prepared by closed space sublimation (CSS) method at a substrate temperature 500°C . The films are treated chemically by dipping in low concentrated, 0. 2g/500ml, AgN03 solution for different period of time i.e., 30 seconds, 60 seconds, 120 seconds, 180 seconds and 240 seconds. The effects of dipping time on the electrical and optical properties have been studied. D.C. electrical resistivity of the films measured by Vander Pauw method showed that low resistive films have been achieved. The conductivity type was checked by hot probe method, p-type films were formed. The optical properties of these films i.e., the films thickness, optical energy band gap and the absorption coefficient have been calculated from the transmission spectra between 400 nm-2000nm recorded by UV-VISNIR spectrometer. The optical transmission in the visible region decreased due to doping of sil ver and shift in the optical band gap was observed. The structure of different films have been studied by the method of x-ray diffraction using CU-Ka l radiation and the composition of the film was measured by atomic absorption spectrometer.