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Controllable epitaxy of quasi-one-dimensional topological insulator α-Bi4Br4 for the application of saturable absorber.
- Source :
- Applied Physics Letters; 2/28/2022, Vol. 120 Issue 9, p1-6, 6p
- Publication Year :
- 2022
-
Abstract
- Bismuth bromide (α-Bi<subscript>4</subscript>Br<subscript>4</subscript>) can demonstrate various exotic topological states, including higher-order topological insulator with hinge states and quantum spin Hall insulator with helical edge states. To date, α-Bi<subscript>4</subscript>Br<subscript>4</subscript> nanowires can be obtained by using the exfoliation method from the bulk. However, it is still a great challenge to efficiently prepare α-Bi<subscript>4</subscript>Br<subscript>4</subscript> nanowires suitable for potential applications, e.g., saturable absorber in ultrafast pulsed fiber lasers. Here, we report the controllable growth of α-Bi<subscript>4</subscript>Br<subscript>4</subscript> thin films consisting of nanowires via molecular beam epitaxy technique. We show that the morphology of the α-Bi<subscript>4</subscript>Br<subscript>4</subscript> nanowires depends on the growth temperature and BiBr<subscript>3</subscript> flux. In addition, we also achieve α-Bi<subscript>4</subscript>Br<subscript>4</subscript> nanowires on NbSe<subscript>2</subscript> and gold substrates. Furthermore, we performed the saturable absorption property of α-Bi<subscript>4</subscript>Br<subscript>4</subscript> thin films with a modulation depth of 21.58% and mode-locking at 1556.4 nm with a pulse width of 375 fs in the pulsed fiber lasers. Those results demonstrate the synthesis of quasi-1D topological material α-Bi<subscript>4</subscript>Br<subscript>4</subscript>, which is expected to be used for the fundamental research of topological physics and potential applications in optical devices. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00036951
- Volume :
- 120
- Issue :
- 9
- Database :
- Complementary Index
- Journal :
- Applied Physics Letters
- Publication Type :
- Academic Journal
- Accession number :
- 155580032
- Full Text :
- https://doi.org/10.1063/5.0083807