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

Title
Carrier Modulation in Bi2Te3-Based Alloys via Interfacial Doping with Atomic Layer Deposition
Authors
김진상백승협김성근김광천임상순이승혁Hyung-Ho Park
Keywords
carrier modulation; atomic layer deposition; Bi2Te3
Issue Date
2020-06
Publisher
Coatings
Citation
VOL 10, NO 6, 572
Abstract
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 Bi2Te2.7Se0.3 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 e ective surface area. Therefore, the proposed approach would provide opportunities to precisely optimize the carrier concentration for high thermoelectric performance.
URI
https://pubs.kist.re.kr/handle/201004/71490
ISSN
2079-6412
Appears in Collections:
KIST Publication > Article
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