Very High Thermopower of Bi Nanowires with Embedded Quantum Point Contacts

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• 作者：Eyal Shapira ; Amir Holtzman ; Debora Marchak ; Yoram Selzer
• 刊名：Nano Letters
• 出版年：2012
• 出版时间：February 8, 2012
• 年：2012
• 卷：12
• 期：2
• 页码：808-812
• 全文大小：313K
• 年卷期：v.12,no.2(February 8, 2012)
• ISSN：1530-6992

文摘

Quantum confinement effects in bismuth (Bi) nanowires (NWs) are predicted to impart them with high thermopower values and hence make them efficient thermoelectric materials. Yet, boundary scattering of charge carriers in these NWs operating in the diffusion transport regime mask any quantum effects and impede their use for nanoscale thermoelectric applications. Here we demonstrate quantum confinement effects in Bi NWs by forming in their structure ballistic quantum point contacts (QPCs) leading to exceptionally high thermopower values (S > 2 mV/K). The power factor, S²G, of the QPCs is maximized at G 0.25G₀ (where G₀ is the quantum of conductance) within agreement with a one-band model with step edge characteristics.

Keywords:

Thermopower; Seebeck coefficient; quantum point contact; quantum confinement; nanowires