Chemically Switchable n‑Type and p‑Type Conduction in Bismuth Selenide Nanoribbons for Thermoelectric Energy Harvesting

• Published in: ACS nano 2021-02, Vol.15 (2), p.2791-2799
• Main Authors: Xiong, Yucheng, Zhou, Guoqing, Lai, Nien-Chu, Wang, Xiaomeng, Lu, Yi-Chun, Prezhdo, Oleg V, Xu, Dongyan
• Format: Article
• Language: English
• ISSN: 1936-0851; 1936-086X
• DOI: 10.1021/acsnano.0c08685

Realizing switchable n-type and p-type conduction in bismuth selenide (Bi2Se3), a traditional thermoelectric material and a topological insulator, is highly beneficial for the development of thermoelectric devices and also of great interest for spintronics and quantum computing. In this work, switching between n-type and p-type conduction in single Bi2Se3 nanoribbons is achieved by a reversible copper (Cu) intercalation method. Density functional theory calculations reveal that such a switchable behavior arises from the electronic band structure distortion caused by the high-concentration Cu intercalation and the Cu substitution for Bi sites in the host lattice. A proof-of-concept in-plane thermoelectric generator is fabricated with one pair of the pristine n-type and intercalated p-type Bi2Se3 nanoribbons on a microfabricated device, which gives rise to an open-circuit voltage of 4.8 mV and a maximum output power of 0.3 nW under a temperature difference of 29.2 K. This work demonstrates switchable n-type and p-type electrical conduction in Bi2Se3 nanoribbons via a facile chemical approach and the practical application of nanoribbons in a thermoelectric device.