Structural properties of Bi{sub 2}Te{sub 3} topological insulator thin films grown by molecular beam epitaxy on (111) BaF{sub 2} substrates

Journal Article · Thu Apr 28 04:00:00 EDT 2016 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4947266· OSTI ID:22594659

Rappl, Paulo H. O.; Abramof, Eduardo ^[1]; Morelhão, Sérgio L. ^[2]

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1. LAS, Instituto Nacional de Pesquisas Espaciais, CP 515, 12245-970 São José dos Campos, SP (Brazil)
2. Instituto de Física, Universidade de São Paulo, CP 66318, 05315-970 São Paulo, SP (Brazil)

Structural properties of topological insulator bismuth telluride films grown epitaxially on (111) BaF{sub 2} with a fixed Bi{sub 2}Te{sub 3} beam flux were systematically investigated as a function of substrate temperature and additional Te flux. A layer-by-layer growth mode is observed since the early stages of epitaxy and remains throughout the whole deposition. Composition of the epitaxial films produced here stays between Bi{sub 2}Te{sub 3} and Bi{sub 4}Te{sub 5}, as determined from the comparison of the measured x-ray diffraction curves with calculations. The substrate temperature region, where the growth rate remains constant, is found to be the most appropriate to obtain ordered Bi{sub 2}Te{sub 3} films. Line width of the L = 18 Bi{sub 2}Te{sub 3} diffraction peaks as low as 140 arcsec was obtained, indicating high crystalline quality. Twinning domains density rises with increasing growth temperature and reducing Te extra flux. X-ray reflectivity curves of pure Bi{sub 2}Te{sub 3} films with thickness from 165 to 8 nm exhibited well defined interference fringes, evidencing homogeneous layers with smooth surface. Our results demonstrate that Bi{sub 2}Te{sub 3} films with very well controlled structural parameters can be obtained. High structural quality Bi{sub 2}Te{sub 3} films as thin as only eight quintuple layers grown here are promising candidates for intrinsic topological insulator.

• OSTI ID: 22594659
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 16 Vol. 119; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
BARIUM FLUORIDES
BISMUTH TELLURIDES
COMPARATIVE EVALUATIONS
DENSITY
DIAGRAMS
LAYERS
LINE WIDTHS
MOLECULAR BEAM EPITAXY
MOLECULAR BEAMS
REFLECTIVITY
SUBSTRATES
SURFACES
THICKNESS
THIN FILMS
TOPOLOGY
X RADIATION
X-RAY DIFFRACTION