K-promoted oxidation of GaSb (1 1 0): the effects of potassium coverage and substrate temperature

Potassium-promoted oxidation of the GaSb (110) surface has been comparatively studied under different combinations of substrate temperature and K-coverage using X-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy. Various species of oxygen (O2−, O22− and O2−) have been observed under different conditions. We find that K-coverage and a proper substrate temperature (500K) is favorable for the oxidation of the semiconductor, with temperature being even more effective than K-coverage. The efficiency of the promoted oxidation is discussed for different experimental conditions. We conclude that the oxidation ability of the oxygen species follows the order KO2, K2O2 and K2O, and that the fraction of the different species depends on the local atomic ratio of K/O and the substrate temperature.