• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.10a
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• pp.381-382
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• 2018

Subthreshold swings (SSs) and on-currents of four types of junctionless nanowire tunnel field-effect transistor(JLNW-TFET) are observed. Ge-Si structure for the source-channel junction has the highest drive current among Si-Si, Si-Ge, and Ge-Ge junction, and the drive current increases up to 1000 times compared to others. Minimum SS of Si-Si junction is reduced by up to 5 times more than others.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.10
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• pp.825-829
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• 2015

Theoretical calculations suggest that the thermoelectric figure of merit (ZT) can be improved by introducing a core-shell heterostructure to a semiconductor nanowire because of the reduced thermal conductivity of the nanowire. To experimentally verify the decrease in thermal conductivity in core-shell nanowires, the thermal conductivity of Ge-SixGe1-x core-shell nanowires grown by chemical vapor deposition (CVD) was measured using suspended microdevices. The silicon composition (Xsi) in the shells was measured to be about 0.65, and the remainder of the germanium in the shells was shown to play a role in decreasing defects originating from the lattice mismatch between the cores and shells. In addition to the standard four-point current- voltage (I-V) measurement, the measurement configuration based on the Wheatstone bridge was attempted to enhance the measurement sensitivity. The measured thermal conductivity values are in the range of 9-13 W/mK at room temperature and are lower by approximately 30 than that of a germanium nanowire with a comparable diameter.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.9
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• pp.621-627
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• 2016

In this study, we present a model that can be used to calculate the phonon-surface scattering rate directly from the experimental data on phonon mean free path (MFP) spectra of nanostructures. Using this model and the recently reported length-dependent thermal conductivity measurements on $Si_{0.9}Ge_{0.1}$ nanowires (NWs), we investigate the spectral reduced MFP distribution and the spectral phonon-surface scattering rate in the $Si_{0.9}Ge_{0.1}$ NWs. From the results, it is found that the phonon transport properties with the material and the phonon frequency dependency of the spectral phonon-surface scattering rate per unit length of the NW. The model presented in this study can be used for developing heat transfer analysis models of nanomaterials, and for determining the optimum design for tailoring the heat transfer characteristics of nanomaterials for future applications of phonon nanoengineering.