Quantitative Thermopower Profiling across a Silicon p–n Junction with Nanometer Resolution

Byeonghee Lee †, Kyeongtae Kim ‡, Seungkoo Lee §,Jong Hoon Kim §, Dae Soon Lim §, Ohmyoung Kwon*‡, and Joon Sik Lee †

^† School of Mechanical and Aerospace Engineering,Seoul National University, Seoul 151-744, Korea

^‡ Department of Mechanical Engineering, Korea University, Seoul 136-701, Korea

^§ Department of Materials Science and Engineering,Korea University, Seoul 136-701, Korea

Nano Lett., Article ASAP

DOI: 10.1021/nl301359c

Publication Date (Web): August 13, 2012

Copyright © 2012 American Chemical Society

*E-mail: omkwon@korea.ac.kr.

Thermopower (S) profiling with nanometer resolution is essential for enhancing the thermoelectric figure of merit, ZT, through the nanostructuring of materials and for carrier density profiling in nanoelectronic devices. However, only qualitative and impractical methods or techniques with low resolutions have been reported thus far. Herein, we develop a quantitative S profiling method with nanometer resolution, scanning Seebeck microscopy (SSM), and batch-fabricate diamond thermocouple probes to apply SSM to silicon, which requires a contact stress higher than 10 GPa for stable electrical contact. The distance between the positive and negative peaks of the S profile across the silicon p–n junction measured by SSM is 4 nm, while the theoretical distance is 2 nm. Because of its extremely high spatial resolution, quantitative measurement, and ease of use, SSM could be a crucial tool not only for the characterization of nano-thermoelectric materials and nanoelectronic devices but also for the analysis of nanoscale thermal and electrical phenomena in general.