Gupta, Bipin Kumar and Sultana, Rabia and Singh, Satbir and Singh, Vijeta and Awana, Geet and Gupta, Anurag and Singh, Bahadur and Srivastava, A. K. and Srivastava, O. N. and Auluck, S. and Awana, V. P. S.
(2018)
Unexplored photoluminescence from bulk and mechanically exfoliated few layers of Bi2Te3.
Scientific Reports, 8.
pp. 9205-9210.
ISSN 2045-2322
Abstract
We report the exotic photoluminescence (PL) behaviour of 3D topological insulator Bi2Te3 single crystals grown by customized self-flux method and mechanically exfoliated few layers (18 +/- 2 nm)/thin flakes obtained by standard scotch tape method from as grown Bi2Te3 crystals. The experimental PL studies on bulk single crystal and mechanically exfoliated few layers of Bi2Te3 evidenced a broad red emission in the visible region from 600-690 nm upon 375 nm excitation wavelength corresponding to optical band gap of 2 eV. These findings are in good agreement with our theoretical results obtained using the ab initio density functional theory framework. Interestingly, the observed optical band gap is several times larger than the known electronic band gap of similar to 0.15 eV. The experimentally observed 2 eV optical band gap in the visible region for bulk as well as for mechanically exfoliated few layers Bi2Te3 single crystals clearly rules out the quantum confinement effects in the investigated samples which are well known in the 2D systems like MoS2, WS2, WSe2, and MoSe2 for 1-3 layers.
| Item Type: |
Article
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| Additional Information: |
Copyright for this article belongs to Nature Publishing Group. |
| Subjects: |
Materials Science |
| Divisions: |
UNSPECIFIED |
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| Date Deposited: |
03 Feb 2020 11:29 |
| Last Modified: |
03 Feb 2020 11:29 |
| URI: |
http://npl.csircentral.net/id/eprint/3725 |
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