Influence of oxygen on the crystalline : amorphous transition in gallium nitride films

Oxygen is a common impurity in nitride-based materials that affects the properties of technologically important materials such as gallium nitride semiconductors. In this work, the influence of oxygen on the structural evolution of GaN films is investigated using near-edge X-ray absorption fine structure (NEXAFS). The combined spectra of Ga L3-edge, N K-edge, and O K-edge indicate that the gallium coordination, formed by a mixture of oxide and nitride bonds, is directly dependent on the concentration of oxygen in the films. Below 24 atom % oxygen, gallium atoms are tetrahedrally coordinated within the films, while at higher concentrations the octahedral environment persists