Strategy for accurate thermal biasing at the nanoscale

Nanotechnology. 2020. Vol. 31. P. 1–11.

Denisov A. O., Tikhonov E., Piatrusha S. U., Khrapach I. N., Rossella F., Rocci M., Sorba L., Roddaro S., Khrapai V.

We analyze the benefits and shortcomings of a thermal control in nanoscale electronic
conductors by means of the contact heating scheme. Ideally, this straightforward approach
allows one to apply a known thermal bias across nanostructures directly through metallic leads,
avoiding conventional substrate intermediation. We show, by using the average noise
thermometry and local noise sensing technique in InAs nanowire–based devices, that a
nanoscale metallic constriction on a SiO2 substrate acts like a diffusive conductor with
negligible electron-phonon relaxation and non-ideal leads. The non-universal impact of the
leads on the achieved thermal bias—which depends on their dimensions, shape and material
composition—is hard to minimize, but is possible to accurately calibrate in a properly designed
nano-device. Our results allow to reduce the issue of the thermal bias calibration to the
knowledge of the heater resistance and pave the way for accurate thermoelectric or similar
measurements at the nanoscale.

Keywords: electron-phonon relaxation, Thermoelectricity, noise thermometry