Electrical Defect State Distribution in Single Crystal ZnO Schottky Barrier Diodes

The characterization of defect states in a hydrothermally grown single crystal of ZnO was performed using deep-level transient spectroscopy in the temperature range of 77-340 K. The native intrinsic defect energy level within the ZnO band gap occurred in the depletion region of ZnO Schottky barrier diodes. A major defect level was observed, with a thermal activation energy of 0.27 eV (E3) within the defect state distribution from 0.1 to 0.57 eV below the conduction band minimum. We confirmed the maximum defect concentration to be 3.66 x 10(16) cm(-3) at 0.27 eV (E3). As a result, we clearly confirmed the distribution of density of defect states in the ZnO band gap.