Carrier Modulation in Bi2Te3-Based Alloys via Interfacial Doping with Atomic Layer Deposition

Coatings

Sang-Soon Lim¹  Seunghyeok Lee¹  Kwang-Chon Kim¹  Jin-Sang Kim¹  SeongKeun Kim¹  Seung-Hyub Baek¹  Hyung-Ho Park² 

[1] Center for Electronic Materials, Korea Institute of Science and Technology, Seoul 02792, Korea;Department of Materials Science and Engineering, Yonsei University, Seoul 03722, Korea;

关键词: carrier modulation;    atomic layer deposition;    Bi₂Te₃;   

DOI  :  10.3390/coatings10060572

来源: DOAJ

【 摘 要 】

The carrier concentration in Bi₂Te₃-based alloys is a decisive factor in determining their thermoelectric performance. Herein, we propose a novel approach to modulate the carrier concentration via the encapsulation of the alloy precursor powders. Atomic layer deposition (ALD) of ZnO and SnO₂ was performed over the Bi₂Te_2.7Se_0.3 powders. After spark plasma sintering at 500 °C for 20 min, the carrier concentration in the ZnO-coated samples decreased, while the carrier concentration in the SnO₂-coated samples increased. This trend was more pronounced as the number of ALD cycles increased. This was attributed to the intermixing of the metal ions at the interface. Zn²⁺ substituted for Bi³⁺ at the interface acted as an acceptor, while Sn⁴⁺ substituted for Bi³⁺ acted as a donor. This indicates that the carrier concentration can be adjusted depending on the materials deposited with ALD. The use of fine powders changes the carrier concentration more strongly, because the quantity of material deposited increases with the effective surface area. Therefore, the proposed approach would provide opportunities to precisely optimize the carrier concentration for high thermoelectric performance.

【 授权许可】

Unknown