Comparative study of activated oxygen uptake on HgTe, Hg_0.69Cd_0.31Te, and CdTe

Soft‐x‐ray photoemission spectroscopy was used to monitor the uptake of oxygen on the (110) faces of HgTe, Hg_0.69Cd_0.31Te, and CdTe during the formation of roughly two monolayers of oxide. The oxidation was activated by a hot filament in line‐of‐sight of the sample surface. The oxides formed contain Cd and Te; whereas, Hg is lost from the surface during the initial stages of oxide formation. The rate of oxidation for the Hg_0.69Cd_0.31Te sample was found to be 69% as great as that for the binary HgTe, and lower than observed for CdTe. The scaling of oxidation rate with the number of Hg–Te bonds between HgTe and the x=0.31 alloy, together with the observed release of Hg upon oxidation, suggests the importance of breaking the Hg–Te bond as a step in the oxidation process. Evidence for an unstable character of the oxide on the Hg containing compounds is also presented.