Defect control in p-type oxide semiconductor for device application

用X射线光电子能谱（XPS）研究了Cu_2O膜表面和Cu_2O/Al_2O_x界面Cu的价态。结果表明，界面处Cu的价态始终为Cu^<2+>，且不受沉积顺序的影响。真空退火能有效地将界面处的Cu^<2+>还原为Cu^+，但当界面上沉积厚膜时，真空退火不能有效地将界面处的Cu^<2+>还原为Cu^+。

Cu valency at the Cu_2O film surface and Cu_2O/Al_2O_x interface were studied by X-ray photoelectron spectroscopy. We revealed that Cu valency at the interfaces is always Cu^<2+> and this result was not affected by deposition order. We also revealed that vacuum annealing was effective to reduce Cu^<2+> to Cu^+at the interface, but it does not work when thick film was deposited on the interface.