whereas in-situ vacuum annealing removes surface arsenic pile-up. After the atomic layer deposition of HfO 2 , native oxides were considerably reduced compared to that in as-received epi-layers, strongly suggesting the self-clean mechanism. Valence and conduction band offsets are measured to be 3.37±0.1eV, 1.80±0.3eV for In 0.53 Ga 0.47 As and 3.00±0.1eV, 1.47±0.3eV for In 0.52 Al 0.47 As, respectively.