Epitaxial growth and characterization of Bi1−xSbx thin films on (0001) sapphire substrates
Yu-Sheng Huang,
Saurav Islam,
Yongxi Ou,
Supriya Ghosh,
Anthony Richardella,
K. Andre Mkhoyan,
Nitin Samarth
Affiliations
Yu-Sheng Huang
Department of Physics, Pennsylvania State University, University Park, Pennsylvania 16802, USA
Saurav Islam
Department of Physics, Pennsylvania State University, University Park, Pennsylvania 16802, USA
Yongxi Ou
Department of Physics, Pennsylvania State University, University Park, Pennsylvania 16802, USA
Supriya Ghosh
Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, USA
Anthony Richardella
Department of Physics and Materials Research Institute, Pennsylvania State University, University Park, Pennsylvania 16802, USA
K. Andre Mkhoyan
Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, USA
Nitin Samarth
Department of Physics, Department of Materials Science and Engineering, and Materials Research Institute, Pennsylvania State University, University Park, Pennsylvania 16802, USA
We report the molecular beam epitaxy of Bi1−xSbx thin films (0 ≤ x ≤ 1) on sapphire (0001) substrates using a thin (Bi,Sb)2Te3 buffer layer. The characterization of the films using reflection high energy diffraction, x-ray diffraction, atomic force microscopy, and scanning transmission electron microscopy reveals the epitaxial growth of films of reasonable structural quality. This is further confirmed via x-ray diffraction pole figures that determine the epitaxial registry between the thin film and the substrate. We further investigate the microscopic structure of thin films via Raman spectroscopy, demonstrating how the vibrational modes vary as the composition changes and discussing the implications for the crystal structure. We also characterize the samples using electrical transport measurements.
