TY - JOUR

T1 - Formation of well-ordered surfaces of Bi2-xSbxTe3-ySey topological insulators using wet chemical treatment

AU - Tarasov, A. S.

AU - Kumar, N.

AU - Golyashov, V. A.

AU - Akhundov, I. O.

AU - Ishchenko, D. V.

AU - Kokh, K. A.

AU - Bazhenov, A. O.

AU - Stepina, N. P.

AU - Tereshchenko, O. E.

N1 - The authors acknowledge support from Ministry of Science and Higher Education of the Russian Federation Grant No. 075-15-2020-797 (13.1902.21.0024).

PY - 2024/3/15

Y1 - 2024/3/15

N2 - The surface preparation of topological insulators (TIs) is a critical task in order to realize their efficient applications. A chemical treatment in an anhydrous solution of hydrogen chloride in isopropanol (HCl-iPA) and a subsequent annealing at relatively low temperature in ultrahigh vacuum (UHV) was successfully used for the surface preparation of bulk 3D (0 0 0 1) TIs Bi2Te3, Sb2Te3, Bi2Se3 and an MBE - grown Bi2-xSbxTe3-ySey (BSTS) thin films. The surface treatment showed a significant modification of the initial TI surfaces, which was free from the structural disorder, oxidation and chemical impurities determined by X-ray photoelectron spectroscopy and low-energy electron diffraction. The insulating nontrivial bulk gap and well resolved gapless surface states with a linear dispersion of a massless Dirac cone were observed by angle-resolved photoelectron spectroscopy (ARPES). In the BSTS film, the Fermi level is located within the bulk band gap. The negative magnetoconductance corresponding to weak antilocalization demonstrated the contribution of the surface states of BSTS, that promise to be protected from backscattering. The surface treatment method proposed in this work is highly efficient for both bulk and thin TI films that can be useful for the deposition of an insulators/metals to fabricate transistor and spin valve systems.

AB - The surface preparation of topological insulators (TIs) is a critical task in order to realize their efficient applications. A chemical treatment in an anhydrous solution of hydrogen chloride in isopropanol (HCl-iPA) and a subsequent annealing at relatively low temperature in ultrahigh vacuum (UHV) was successfully used for the surface preparation of bulk 3D (0 0 0 1) TIs Bi2Te3, Sb2Te3, Bi2Se3 and an MBE - grown Bi2-xSbxTe3-ySey (BSTS) thin films. The surface treatment showed a significant modification of the initial TI surfaces, which was free from the structural disorder, oxidation and chemical impurities determined by X-ray photoelectron spectroscopy and low-energy electron diffraction. The insulating nontrivial bulk gap and well resolved gapless surface states with a linear dispersion of a massless Dirac cone were observed by angle-resolved photoelectron spectroscopy (ARPES). In the BSTS film, the Fermi level is located within the bulk band gap. The negative magnetoconductance corresponding to weak antilocalization demonstrated the contribution of the surface states of BSTS, that promise to be protected from backscattering. The surface treatment method proposed in this work is highly efficient for both bulk and thin TI films that can be useful for the deposition of an insulators/metals to fabricate transistor and spin valve systems.

KW - Fermi level

KW - Photoemission

KW - Surface state

KW - Surface treatment

KW - Topological insulator

UR - https://www.scopus.com/record/display.uri?eid=2-s2.0-85181891616&origin=inward&txGid=a4f4eb9e9dd4fac6f0ca1d4c58edb235

UR - https://www.mendeley.com/catalogue/903a5eba-09cd-3730-9b76-726fc5d93f0c/

U2 - 10.1016/j.apsusc.2023.159122

DO - 10.1016/j.apsusc.2023.159122

M3 - Article

VL - 649

JO - Applied Surface Science

JF - Applied Surface Science

SN - 0169-4332

M1 - 159122

ER -