Admittance Spectroscopy of Cu-Doped ZnO Crystals

Abstract
An experiment to determine the electronic state of Cu in a ZnO crystal is performed using the admittance spectroscopy technique at the frequency range from 100 Hz to 100 kHz and the temperature range from -160 to +80°C. The results obtained are summarised as follows: Cu behaves as an acceptor in ZnO and its energy level locates at 0.17 eV below the bottom of the conduction band. The values of the electron capture cross section are found to decrease with increasing Cu concentration, and they are determined as 2-12×10-17 cm2.