Effect of O-vacancy defects on the Schottky barrier heights in Ni/SiO2 and Ni/HfO2 interfaces

We perform first-principles density functional calculations to study the electronic structure of Ni/HfO2 and Ni/SiO2 interfaces and the effect of O-vacancy (VO) defects on the Schottky barrier height and the effective work function. We generate two interface models in which Ni is placed on O-terminated HfO2 (1 0 0) and α-quartz (1 0 0) surfaces. As the concentration of VO defects at the interface increases, the p-type Schottky barrier height tends to increase in the Ni/HfO2 interface, due to the reduction of interface dipoles, whereas it is less affected in the Ni/SiO2 interface.