Sulfur passivation effect on HfO2/GaAs interface: A first-principles study

The impact of sulfur passivation on the structural and electronic properties of the HfO2/GaAs interface is investigated by density functional theory with a hybrid functional. The gap states at the HfO2/GaAs interface arise from three major contributions: Ga 3+ and partial oxidation, As-As dimers, and Ga dangling bonds. By introducing S atoms at the interface, the removal of the gap states within the lower half of the GaAs band gap is observed, while the gap states in the upper half are pushed upward by similar to 0.15 eV. (c) 2011 American Institute of Physics. [doi:10.1063/1.3597219]