Research of Metal-Nonmetal Transition of Electron-Hole System under Size Quantization in Bi in Strong Magnetic Field

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By a vacuum evaporation technique, bismuth thin films were prepared on BaF_2 single crystal substrate with (111) surface. To improved the degradation of films due to a misfiting of the lattice constant between Bi and BaF_2 by about 3.6%, the heat treating was carried out at a temperature just below the melting point(273ﾟC). By X ray analysis, it was confirmed that the films were single crystal and had a preferred orientation perpendicular to the surface of the substrate. The experimental results are summarized as follows :(1) Bi thin films were prepared reproducibly on BaF_2 single crystal substrate at around 80ﾟC.(2) Flat surface with layring growth were obtained for films with different thickness from 140*to2800*.(3) A classical size effect was confirmed for the thickness and temperature dependence of electrical transport for the films with different thickness from 140* to 2800*.(4) The size quantization with a period of de Broglie wave length was also confirmed.(5) The metal semiconductor transition was confirmed in the thickness dependence of carriers between 420* and 560*.