From monolayer to thin films: engineered bandgap in CVD grown Bi2Se(3−x)Sx topological insulator alloys

Michal Poplinger, Dimitris Kaltsas, Chen Stern, Pilkhaz Nanikashvili, Adi Levi, Rajesh K. Yadav, Sukanta Nandi, Yuxiao Wu, Avinash Patsha, Ariel Ismach, Ashwin Ramasubramaniam, Amaia Pesquera, Amaia Zurutuza, Ioanna Zergioti, Leonidas Tsetseris, Tomer Lewi, Doron Naveh

Research output: Contribution to journalArticlepeer-review

Abstract

Topological insulators, a class of materials possessing bulk bandgap and metallic surface states with a topological nontrivial symmetry, are considered promising candidates for emerging quantum and optoelectronic applications. However, achieving scalable growth and control over the parameters including thickness, carrier density, bulk bandgap, and defect density remains a challenge in realizing such applications. In this work, we show the scalable growth of topological insulator alloys Bi2Se(3−x)Sx and demonstrate composition-tunable bandgap, using chemical vapor deposition (CVD). A bandgap increase of up to ∼40% at a sulfur concentration of ∼15% is demonstrated. Correspondingly, the real part (n) of the refractive index is reduced in the alloy by ∼25% relative to that of Bi2Se3. Additionally, electronic transport measurements indicate a bulk p-type doping and field-effect tunable metallic surface states of the alloy. This work paves the way for the controlled growth of topological insulators, free from surface-state pinning, suitable for quantum optoelectronics and spintronics applications.

Original languageEnglish
JournalJournal of Materials Chemistry C
Volume82
Issue number4
DOIs
StatePublished - 17 Jan 2024

Bibliographical note

Publisher Copyright:
© 2024 The Royal Society of Chemistry

Funding

This work was supported by the European Union's Horizon 2020 research and innovation program under Grant Agreement No. 801389 (Project LEAF-2D). A. P. and A. I. acknowledge the generous support from the Israel Science Foundation, grant number 2596/21.

FundersFunder number
Israel Science Foundation2596/21
Horizon 2020801389

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