Elaboration des couches minces du semiconducteur ZnO dopées au Cobalt et étude de leurs propriétés structurales, optiques et électriques

Abstract

The present work consists in the elaboration and characterization of the undoped and cobalt-doped ZnO with different concentrations of cobalt (Co) (0.5, 1, 5 and 10% in weight) thin films in order to improve the structural, morphological, optical and electrical properties of ZnO. The samples were prepared using the Sol-Gel method and deposited on glass substrates by the Dip-coating ""Dipping-Drawing"" technique. Structural characterization showed the formation of ZnO of hexagonal structure (wurtzite) with a preferential orientation according to plane (002) and made it possible to determine the nanometric size of the crystallites. The SEM and AFM images revealed the nanometric character of our layers. Raman scattering confirmed the results of the XRD, namely the formation of ZnO with an hexagonal structure (wurtzite). UV-visible spectroscopy has shown that our layers have a transparency, in the visible, which varies between 80 and 98%. It has shown also that the gap decreases with the increase in doping. The photoluminescence of the films showed ultraviolet (UV) and visible emissions related to defects. The codoping of aluminum to cobalt allowed us also to improve the structural and optical properties.