Projects / Programmes
Development of "Real" Bi2Se3-Based Topological Insulator with a High Bulk Resistivity
| Code |
Science |
Field |
Subfield |
| 2.04.00 |
Engineering sciences and technologies |
Materials science and technology |
|
| Code |
Science |
Field |
| 2.10 |
Engineering and Technology |
Nano-technology |
topologocal insulators, 2D crystal structures, structural defects, electron transport properties, spintronic tehnology,
Data for the last 5 years (citations for the last 10 years) on
June 28, 2024;
A3 for period
2018-2022
Data for ARIS tenders (
04.04.2019 – Programme tender,
archive
)
| Database |
Linked records |
Citations |
Pure citations |
Average pure citations |
| WoS |
284 |
9,762 |
9,329 |
32.85 |
| Scopus |
292 |
10,784 |
10,317 |
35.33 |
Researchers (3)
| no. |
Code |
Name and surname |
Research area |
Role |
Period |
No. of publicationsNo. of publications |
| 1. |
34949 |
PhD Mattia Fanetti |
Materials science and technology |
Researcher |
2021 - 2024 |
0 |
| 2. |
32783 |
PhD Sandra Gardonio |
Materials science and technology |
Researcher |
2021 - 2024 |
0 |
| 3. |
11991 |
PhD Matjaž Valant |
Materials science and technology |
Head |
2021 - 2024 |
0 |
Organisations (1)
| no. |
Code |
Research organisation |
City |
Registration number |
No. of publicationsNo. of publications |
| 1. |
1540 |
University of Nova Gorica |
Nova Gorica |
5920884000 |
0 |
Abstract
Topological insulators (TI), such as Bi2Se3 with a tetradymite crystal structure, are insulators in their bulk but have protected conducting states on their surface, called topological surface states (TSS). TSS are spin polarized and, therefore, very attractive for applications in low-energy electronic, spintronic and plasmonic technologies as well as quantum computing and catalysis. The main problem that currently hinders the application of the TI materials in these technologies is their severe n-type doping due to the presence of defects (predominantly anion vacancies). Because of that they exhibit non-polarized bulk current making them more like a bad metal than an insulator. Achieving the surface-dominated spin-polarized current is of key importance for the advanced TI-based technologies, however it remains a challenging task. The objective of this project is to tackle this problem by: (i) exploring the innovative approach – gold pump – for the reduction of defect concentration and increase in the bulk resistivity of Bi2Se3 towards Mott’s limit (3·10-4 cm-3) and (ii) studying the local defect structures in the modified Bi2Se3-based TI crystals in order to understand alternative approaches that can be used to increase the bulk resistivity. The so-called gold-pump is a post-processing procedure that has been developed at the applicant institution based on studies of a chemical interaction between Au and Bi2Se3. It was shown that the gold, deposited on the surface of Bi2Se3, tends to draw some Bi out of the crystal into the Au-Bi alloy. Within the Bi2Se3 crystal this process creates Bi vacancies that annihilates with the Se vacancies and therefore reduces the level of n-type doping. Not only the gold-pump procedure but also alternative approaches for reduction of the vacancies will be explored, such as isovalent substitution to increase the vacancy formation energy, aliovalent substitution for charge compensation, and novel hydrothermal synthesis techniques. All these approaches will be supported by synchrotron-based studies of the surface electron structures and transport measurements including Hall measurements to determine the charge carrier concentrations. An important benefit of this project is that we will advance our processing studies with the new knowledge on the crystallography and dynamics of the point defects obtained by the state-of-the-art microscopy. A holistic approach for the electron-probed defect site location, chemical environment, and defect dynamics will be applied and developed at the partner institution in Switzerland for bulk and exfoliated Bi2Se3-based systems produced in Slovenia. We expect that this proposed project will deliver valuable results on the defect chemistry of tetradymites. We will apply this new knowledge for the development of the novel processing and post-processing techniques for the reduction of the Bi2Se3 point defect concentration towards the Mott’s limit. Therefore, the final aim is to prepare a real topological insulator with the insulating bulk characteristics, which will allow further progress in development of the TI-based devices that is now halted due to the conductivity issues.
