Abstract
GaAs (001) surface ultrasonically cleaned under running de-ionized water (U-RDIW) is investigated by reflection high-energy electron diffraction (RHEED). The RHEED observations of U-RDIW-treated surfaces show a spotty (1×1) pattern at room temperature and a (2×1) streaky surface reconstruction pattern at 360 °C. The experimental results indicate that chemically clean and damage-free GaAs surfaces can be produced by U-RDIW treatment. We discuss surface structures before/after heating using a hydrogen- terminated model.