Surface structural dependence of cesium adsorption on the α-Al2O3(0001) surface

Abstract

The structural dependence of Cs adsorption on the α‐Al2O3(0001) surface has been studied using a combination of surface analytical techniques. The unreconstructed or (1×1) surface shows a high initial Cs adsorption probability of 0.9 based on reflection mass spectrometry (RMS). This value decreases rapidly after a critical Cs coverage of 1.5×1014 atoms/cm2 is reached. Thermally‐induced surface reconstruction to form an O deficient surface results in a decrease in the critical coverage, probability and capacity for Cs adsorption. Low energy electron diffraction (LEED) demonstrates that a predominantly (3√3×√3)R30° surface yields an initial adsorption probability of 0.5 while a predominantly (√31×√31)R±9° yields a value of 0.3. Thermal desorption mass spectrometry (TDMS) shows that surface reconstruction suppresses the high binding energy states of Cs, consistent with the observed changes in adsorption probability. X‐ray photoelectron spectroscopy (XPS) provides no direct evidence for formal oxidative/reduc...