Potentiodynamic oxidation of HgCdTe surface formed by fracture in solution

The initial stages of the anodic oxidation of HgTe and HgCdTe were studied by applying a potentiostatic anodic scan to a fresh surface of the material, which was obtained by fracturing it in the anodizing solution and by inspecting it using Auger electron spectroscopy. It was found that a stable oxide formation is preceded by the dissolution of both the CdTe and the HgTe fractions of the alloy which behave as if they were separate entities. The dissolution of the CdTe fraction does not lead to the formation of a stable oxide; this is formed only after the dissolution of mercury. Following the HgTe dissolution peak, a potential region is observed in which the oxide grows with a current efficiency of unity. This implies that mercury should be a major constituent in the oxide and its marginal Auger signal in the oxide is attributed to the evaporation of the volatile HgO content under the action of the electron beam. Taking this into account, the oxide composition on Hg/sub 0.79/Cd/sub 0.21/Te is estimated to be Hg/sub 0.4/Cd/sub 0.6/TeO/sub 3/