Nanoelectronics and positron diffusion study of Zn1−xCuxO thin films

Abstract

ZnO has received much attention over the past few years because it has a wide range of properties that depend on doping, including a range of conductivity from metallic to insulating, high transparency, piezoelectricity, chemical-sensing effects, room-temperature ferromagnetism, and huge magneto-optic and wide-bandgap semiconductivity. Its nano-form have been widely accepted as a source of functional material for various applications including optoelectronics and photonics. In the present work Cu doped ZnO thin films are prepared by Chemical Vapour Deposition (CVD) method. Structural and surface morphology are characterized by x-ray diffraction (XRD) and atomic force microscopy (AFM) techniques. A decrease in grain size is observed when Cu is incorporated in the films of ZnO and an interesting aspect of Cu substitution is that it enhances the activation energy in the semiconducting films. Positron Annihilation Spectroscopy (PAS) characterization was performed on the samples to study defects in the nanostructured thin films. Positron annihilation spectroscopy indicated that the doping process has an important influence on the zinc-related vacancies and their clusters in the ZnO particles.