Properties of CdSe polycrystalline thin films grown by chemical bath

Abstract

CdSe polycrystalline thin films were grown onto glass substrates by chemical bath deposition at 65 degrees C. Structural, optical, and electrical properties of samples were characterized. The layers grew in the cubic phase as evidenced by X-ray diffractograms. Using the first derivative of the optical absorption vs. phonon energy curves, two transitions were found, the fundamental at 1.8 eV and a second one at 2.2 eV, respectively. It is worthwhile to mention that the second transition has been reported only for the hexagonal CdSe modification. From the dark conductivity vs. 1/KT behavior on the 100-500 K range, it could be determined an activation energy of 0.3 eV at higher temperatures (>350 K) and a behavior following the variable range hopping model of Mott was satisfied at lower temperature. Electron dispersion spectroscopy measurements indicated stoichiometric CdSe material within the 1% error bar. (C) 1999 The Electrochemical Society. S0013-4651(98)09-081-8. All rights reserved.