Search NASA⌕ Search

Engineering topics

Kim, Kyeongtae

Publications and source records attributed to Kim, Kyeongtae.

3 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2014

Quantification of thermal and contact resistances of scanning thermal probes

Scanning thermal probes are widely used for imaging temperature fields with nanoscale resolution, for studying near-field radiative heat transport and for locally heating samples. In all these applications, it is critical to know the thermal resistance to heat flow within the probe and the thermal contact resistance between the probe and the sample. Here, we present an approach for quantifying the aforementioned thermal resistances using picowatt resolution heat flow calorimeters. The measured contact resistance is found to be in good agreement with classical predictions for thermal contact resistance. The techniques developed here are critical for quantitatively probing heat flows at the nanoscale.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2014

Characterization of nanoscale temperature fields during electromigration of nanowires

Quantitative studies of nanoscale heat dissipation (Joule heating) are essential for advancing nano-science and technology. Joule heating is widely expected to play a critical role in accelerating electromigration induced device failure. However, limitations in quantitatively probing temperature fields—with nanoscale resolution—have hindered elucidation of the role of Joule heating in electromigration. In this work, we use ultra-high vacuum scanning thermal microscopy to directly quantify thermal fields in nanowires during electromigration. Our results unambiguously illustrate that electromigration begins at temperatures significantly lower than the melting temperature of gold. Further, we show that during electromigration voids predominantly accumulate at the cathode resulting in both local hot spots and asymmetric temperature distributions. These results provide novel insights into the microscopic details of hot spot evolution during electromigration and are expected to guide the design of reliable nanoscale functional devices.

36 MATERIALS SCIENCE↗