Deposition of the reactive metals Al and In onto sputtered and cleaved Hg1−xCdxTe surfaces

The interactions of the reactive metals Al and In with both cleaved and sputtered p-type Hg1−xCdxTe surfaces have been investigated using synchrotron radiation-induced ultraviolet photoelectron spectroscopy. The sputtered surfaces are depleted of a fraction of their Hg (∼25% and ∼40% for x=0.21 and x=0.28 material, respectively, relative to the Hg found on the corresponding cleaved surfaces) and are more inverted than the cleaved surfaces with the Fermi level higher in the conduction band. During metal deposition, the cleaved and sputtered surfaces behave similarly: in the initial stages, the metal reacts with the HgTe alloy component to form a metal telluride and Hg, which leaves the surface region. At the same time, the inverted surface becomes more degenerate. After the metal has reacted with all the available HgTe within a certain surface region, an unreacted metallic film grows on the surface. Such identical behavior of the two types of surfaces is explained by the large difference in thermodynamic stability between HgTe and the metal tellurides.