Work

Study of the Annealing Effects of Sputtered Bi 2 Te 3 Thin Films with Full Thermoelectric Figure of Merit Characterization

Year: 2021

Type: article

Abstract: Micro‐thermoelectric (TE) devices have a great potential for future applications in the field of energy harvesting to power autonomous sensors. Bi 2 Te 3 sputtered at elevated substrate temperatures exhibits a high figure of merit ( ZT ) suitable for the fabrication of micro‐TE devices. However, a lift‐off process that does not allow higher substrate temperatures is often used, and although Bi 2 Te 3 is a well‐studied TE material, it lacks full ZT characterization of thin films. Herein, the full TE characterization of sputtered Bi 2 Te 3 thin films is presented, including the charge carrier concentration and mobility, which are deposited at room temperature and postannealed between 150 and 300 °C. The influence of the annealing time and temperature is investigated on a 90 nm‐thick Bi 2 Te 3 film. A maximum ZT of 0.20 is found, which results from the increasing crystallinity and reduction of point defects. To investigate the thickness dependency, Bi 2 Te 3 films with thicknesses of 90, 170, 350, and 470 nm are annealed at 250 °C. A maximum ZT value of 0.26 is observed for the 350 nm Bi 2 Te 3 film. Furthermore, it can be shown that with increasing film thickness, the annealing time has to be increased to maximize ZT .

Source: physica status solidi (RRL) - Rapid Research Letters

DOI: 10.1002/pssr.202100533

Authors: Maksim Naumochkin, Gyu-Hyeon Park, Kornelius Nielsch, Heiko Reith

Institutions: Leibniz Institute for Solid State and Materials Research, Technische Universität Dresden

Language: English

Topic: Advanced Thermoelectric Materials and Devices

Subfield: Materials Chemistry

Field: Materials Science

Domain: Physical Sciences

SDG: Affordable and clean energy

Open Access status: hybrid

Estimated APC paid: $3,800