Investigation of Oxygen Vacancy and Interstitial Oxygen Defects in ZnO Films by Photoluminescence and X-Ray Photoelectron Spectroscopy

ZnO films prepared at different temperatures and annealed at 900°C in
oxygen are studied by photoluminescence (PL) and x-ray photoelectron
spectroscopy (XPS). It is observed that in the PL of the as-grown films the green luminescence (GL) and the yellow luminescence (YL) are related, and after annealing the GL is restrained and the YL is enhanced. The O 1s XPS results also show the coexistence of oxygen vacancy (V_O) and interstitial oxygen (O_i) before annealing and the quenching of the V_O after annealing. By combining the two results it is deduced that the GL and YL are related to the V_O and O_i defects, respectively.