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[2Fa03] Electronic properties of ultrathin Bi2Te3 films grown on CaF2(111)
We have studied the electronic structure and electrical conduction of ultrathin Bi2Te3 films grown on CaF2(111)/Si(111) by molecular beam epitaxy. Angle-resolved photoelectron spectroscopy (ARPES) showed that the electronic structure of the films near the Fermi level consists of a surface band and a conduction band. Sheet electrical conductivity of the films was measured by a home-built UHV-compatible four-point probe. Residual conductivity σ0 measured at 10 K showed a rapid increase above three quintuple layer (QL). ARPES and low-energy electron diffraction (LEED) results indicate that the thickness dependence in σ0 is mainly attributed to the improvement of crystal quality of the films.