Electronic structure of amorphous InGaO3(ZnO)0.5 thin films
Abstract The electronic structure of amorphous semiconductor InGaO 3 (ZnO) 0.5 thin films, which were deposited by radio-frequency magnetron sputtering process, was investigated using X-ray photoelectron spectroscopy and O K -edge X-ray absorption spectroscopy. The overall features of the valence and conduction bands were analyzed by comparing with the spectra of Ga 2 O 3 , In 2 O 3 , and ZnO films. The valence and conduction band edges are mainly composed of O 2 p and In 5 sp states, respectively. The bandgap of the films determined by spectroscopic ellipsometry was approximately 3.2 eV. Further, it is found that the introduction of oxygen gas during the sputter-deposition does not induce significant variations in the chemical states and band structure.