Hybrid functional investigations of point defects in ZnO and β-Ga2O3

Abstract

Metal oxide semiconductors are widely recognized as prime materials for future energy technology along the low-carbon development path. Zinc oxide and gallium oxide, studied in the present thesis, promise highly efficient optoelectronic and electricity conversion devices. Point defects can significantly influence the materials properties of semiconductors, and thus have a defining impact on their functionality, both as enablers and barriers. Understanding and controlling defects is therefore pivotal to the technological development of zinc oxide and gallium oxide. The present work explores defects in zinc oxide and gallium oxide using hybrid functional calculations. Recently developed methodology is em-ployed to predict defect properties that can be compared directly with experimental data from electrical and optical defect spectroscopic techniques, aiding in the identification of prominent and technologically relevant defect signatures, and providing new insights into the defect physics. The studied defects include self-trapped holes and polaronic accep-tors, iron and titanium impurities in gallium oxide, and close-associate cation-oxygen divacancies.