Abstract

We report a low-temperature magneto transport study of Bi2Se3 thin films of different thicknesses (40, 80 and 160 nm), deposited on sapphire (0001) substrates, using radio frequency magnetron sputtering technique. The high-resolution x-ray diffraction measurements revealed the growth of rhombohedral c-axis {0003n} oriented Bi2Se3 films on sapphire (0001). Vibrational modes of Bi2Se3 thin films were obtained in the low wavenumber region using Raman spectroscopy. The surface roughness of sputtered Bi2Se3 thin films on sapphire (0001) substrates were obtained to be ~ 2.26–6.45 nm. The chemical and electronic state of the deposited Bi2Se3 was confirmed by X-ray photoelectron spectroscopy and it showed the formation of Bi2Se3 compound. Resistivity versus temperature measurements show the metallic nature of Bi2Se3 films and a slight up-turn transition in resistivity at lower temperatures < 25 K. The positive magneto-resistance value of Bi2Se3 films measured at low temperatures (2–100 K) confirmed the gapless topological surface states in Bi2Se3 thin films. The quantum correction to the magnetoconductivity of thin films in low magnetic field is done by employing Hikami–Larkin–Nagaoka theory and the calculated value of coefficient ‘α’ (defining number of conduction channels) was found to be 0.65, 0.83 and 1.56 for film thickness of 40, 80 and 160 nm, respectively. These observations indicate that the top and bottom surface states are coupled with the bulk states and the conduction mechanism in Bi2Se3 thin films varied with the film thicknesses.

Details

Title
Signature of weak-antilocalization in sputtered topological insulator Bi2Se3 thin films with varying thickness
Author
Gautam, Sudhanshu 1 ; Aggarwal, V. 1 ; Singh, Bheem 1 ; Awana, V. P. S. 1 ; Ganesan, Ramakrishnan 2   VIAFID ORCID Logo  ; Kushvaha, S. S. 1 

 CSIR- National Physical Laboratory, New Delhi, India (GRID:grid.419701.a) (ISNI:0000 0004 1796 3268); Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India (GRID:grid.469887.c) (ISNI:0000 0004 7744 2771) 
 Birla Institute of Technology and Science (BITS), Department of Chemistry, Hyderabad, India (GRID:grid.469887.c) 
Publication year
2022
Publication date
2022
Publisher
Nature Publishing Group
e-ISSN
20452322
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2675834154
Copyright
© The Author(s) 2022. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.