Heat carrier mean free path spectroscopy with continuous thermal length control from 6 nm to 100 nm

초록

Controlling heat transport at the nanoscale requires detailed knowledge of heat carrier mean free paths (MFPs), especially as device dimensions approach atomic scales. However, existing methods have struggled to resolve MFP spectra below tens of nanometers due to limited spatial resolution. Here, we demonstrate a scanning thermal microscopy (SThM)-based spectroscopy enabling continuous and quantitative measurement of effective thermal conductivity by continuously varying the contact diameter from 6 nm to 100 nm between the SThM probe and specimen. Using this approach, we directly reconstruct accurate MFP spectra for amorphous SiO2, AgSbTe2, Bi2Te3, and single-crystalline silicon at previously inaccessible length scales down to near-interatomic distances. This technique provides unprecedented spatial resolution and accuracy, enabling direct experimental access to short-MFP heat carriers and substantially advancing nanoscale thermal transport analysis. Our approach thus opens significant opportunities for optimizing thermal performance in thermoelectrics, amorphous solids, and nanoelectronic devices.

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