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 (∼1020 cm3) and low mobility [∼8 cm2/(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.
Bibliographical noteFunding Information:
This work was partially supported by the Center for Spintronic Materials, Interfaces and Novel Architectures (C-SPIN), one of the six SRC STARnet Centers, sponsored by MARCO and DARPA and the National Science Foundation Nanoelectronics Beyond 2020 (Grant No. NSF NEB 1124831). The characterization was performed at the Characterization facility (Charfac) supported by MRSEC, funded by NSF. The fabrication was done at Minnesota Nano Center, funded by NSF. We would like to thank Mahendra D. C. and Professor Paul Crowell from the University of Minnesota for their valuable inputs.
© 2018 Author(s).