Growth and characterization of thin anodic oxide films on n-InSb(1 0 0) formed in aqueous solutions

Anodic oxide films were galvanostatically grown on n-InSb(1 0 0) surfaces at various pH in sodium hydroxide (0.1 M NaOH, pH=13), borate buffer (0.075 M Na 2B 4O 7 + 0.3 M H 3BO 3, pH=8.4) and phosphate buffer (0.3 M NH 4H 2PO 4, pH=4.4). Thickness, composition and morphology of the oxide films were determined by various surface analytical techniques such as Auger electron spectroscopy, X-ray photoelectron spectroscopy, scanning and transmission electron microscopy and atomic force microscopy. The oxides comprise mainly In 2O 3 and Sb 2O 3 and the oxide thickness increases with pH. Electrical properties of oxides indicate that the films may be useful as insulators in some device applications.