K-promoted oxidation of GaSb (110): the effects of potassium coverage and substrate temperature

Potassium-promoted oxidation of the GaSb (110) surface has been comparative ly studied under different combinations of substrate temperature and K-cove rage using X-ray photoelectron spectroscopy and ultraviolet photoelectron s pectroscopy. Various species of oxygen (O2-, O-2(2-) and O-2) have been obs erved under different conditions. We find that K-coverage and a proper subs trate temperature (500 K) is favorable for the oxidation of the semiconduct or, with temperature being even more effective than K-coverage. The efficie ncy of the promoted oxidation is discussed for different experimental condi tions. We conclude that the oxidation ability of the oxygen species follows the order KO2, K2O2 and K2O, and that the fraction of the different specie s depends on the local atomic ratio of K/O and the substrate temperature. ( C) 2001 Elsevier Science BN. All rights reserved.