Oxygen vacancies in high dielectric constant oxides La2O3, Lu2O3, and LaLuO3

Abstract

We present first principles calculations of the energy levels of the oxygen vacancy in La2O3, Lu2O3, and LaLuO3. The levels are found to lie above the Si gap when aligned using the experimental band offsets. In hexagonal La2O3, Lu2O3, and LaLuO3, oxygen vacancies with four neighbors behave similarly to those in HfO2, which are identified as the main electron trap, while oxygen vacancies with six neighbors have no negative charged state so that they are less important for charge trapping. Oxygen vacancies in perovskite LaLuO3 only have positive charge state so they do not act as electron trap.