Synchrotron radiation based photoemission studies of indium oxide passivation of ZnO(0001) surface at high temperature.

Passivation of surface reactive ZnO(0001)-Zn terminated surface is carried out by in-situ deposition of indium metal and post deposition annealing at high temperature (600 C - 1000 C). After the every cycle of indium deposition and annealing the ZnO(0001) surface is characterised by synchrotron radiation based photoemission. The photoemission studies confirmed the formation of deposited indium turned into indium oxide (In2O3 and In2Ox) as surface passivation layer. The core level spectra for Zn, C, O, were acquired at different photon energy for high surface sensitivity. Overall core level peaks (Zn 3p, In 4d, O 1s) having average binding shift ranging from 0.5 eV to 0.8 eV. The valance band spectra shows fermi level shift of 0.9 eV after passivation at 1000 C and work function raises form 4.06 eV to 4.77 eV. Downward band bending of ZnO(0001) surface is turned into upward bending of 0.98 eV by indium oxide passivation at high temperature, which is suitable for making ZnO schotty contact and devices.