Weak antilocalization and low-temperature characterization of sputtered polycrystalline bismuth selenide

摘要

We report a thorough crystal and transport characterization of sputtered polycrystalline BixSe1-x (20 nm), grown on a thermally oxidized silicon substrate. The crystal and grain structures of the sample are characterized by transmission electron microscopy. Selected-area electron diffraction shows a highly polycrystalline structure. Transport measurements suggest semiconducting behavior of the BixSe1-x film with a very high carrier concentration (similar to 10(20) cm(3)) and low mobility [similar to 8 cm(2)/(V s)]. High-field magnetoresistance measurements reveal weak antilocalization, to which both the low mobility and the angular dependence suggest an impurity-dominated contribution. Fitting parameters are obtained from 2D magnetoconductivity using the Hikami-Larkin-Nagaoka equation. The variation of the phase coherence length with temperature suggests electron-electron scattering for phase decoherence. Electron-electron interaction theory is used to analyze the low-temperature conductivity. Published by AIP Publishing.