Synchrotron radiation photoemission spectroscopic study of band offsets and interface self-cleaning by atomic layer deposited HfO2 on In0.53Ga0.47As and In0.52Al0.48As

The synchrotron radiation photoemission spectroscopic study was conducted to (a) investigate the surface chemistry of In0.53Ga0.47As and In0.52Al0.48As postchemical and thermal treatments, (b) construct band diagram, and (c) investigate the interface property of HfO2/In0.53Ga0.47As and HfO2/In0.52Al0.48As. Dilute HCl and HF etch remove native oxides on In0.53Ga0.47As and In0.52Al0.47As, whereas in situ vacuum annealing removes surface arsenic pileup. After the atomic layer deposition of HfO2, native oxides were considerably reduced compared to that in as-received epilayers, strongly suggesting the self-clean mechanism. Valence and conduction band offsets are measured to be 3.37 +/- 0.1 and 1.80 +/- 0.3 eV for In0.53Ga0.47As and 3.00 +/- 0.1 and 1.47 +/- 0.3 eV for In0.52Al0.47As, respectively.