I. HgSe is deposited on various semiconductors, forming asemimetal/semiconductor "Schottky barrier" structure. Polycrystalline,evaporated HgSe produces larger Schottky barrier heights on n-typesemiconductors than does Au, the most electronegative of the elementalmetals. The barrier heights are about 0.5 eV greater thanthose of Au on ionic semiconductors such as ZnS, and 0.1 to 0.2eV greater for more covalently bonded semiconductors. A novelstructure,which is both a lattice matched heterostructure and aSchottky barrier, is fabricated by epitaxial growth of HgSe onCdSe using hydrogen transport CVD. The Schottky barrier heightfor this structure is 0.73 ± 0.02 eV, as measured by the photoresponsemethod. This uncertainty is unusually small; and the magnitude isgreater by about a quarter volt than is achievable with Au, inqualitative agreement with ionization potential arguments.
II . The Schottky barrier height of Au on chemically etchedn-Ga1-x AlxAs was measured as a function of x. As x increases, thebarrier height rises to a value of about 1.2 eV at x ≈ 0.45 , thendecreases to about 1.0 eV as x approaches 0.83. The barrier heightdeviates in a linear way from the value predicted by the "commonanion" rule as the AlAs mole fraction increases. This behavior isrelated to chemical reactivity of the Ga1-x AlxAs surface.
