Band alignment and defect states in amorphous GaInZnO thin films grown on SiO 2 /Si substrates

The band alignment and defect states of GaInZnO thin films grown on SiO 2 /Si via radio frequency (RF) magnetron sputtering were investigated by using X‐ray photoelectron spectroscopy, reflection electron energy loss spectroscopy, thermally stimulated exo‐electron emission and photo‐induced current transient spectroscopy.The band gap via reflection electron energy loss spectroscopy was 3.2 eV. The defect states via photo‐induced current transient spectroscopy and thermally stimulated exo‐electron emission were at 0.24, 0.53, 1.69 and 2.01 eV below the conduction band minimum of GIZO thin films, respectively. The defect states at 0.24 and 0.53 eV are related to the field‐effect mobility, and the defect stated at 1.69 and 2.01 eV is related to the oxygen vacancy defect. Copyright © 2016 John Wiley & Sons, Ltd.