  We report herein the pressure dependent thermal contact resistance (Rc)
between Wollaston wire thermal probe and samples which is evaluated within the
framework of an analytical model. This work presents heat transfer between the
Wollaston wire thermal probe and samples at nanoscale for different air
pressure ranging from 1 Pa to 10e5 Pa. We make use of a scanning thermal
microscopy (SThM) for the thermal analysis of two samples, fused silica (SiO2)
and Titanium (Ti), with different thermal conductivities. The thermal probe's
output voltage difference (deltaV) between out-off contact output voltage (Voc)
and in-contact output voltage (Vic) was recorded. The result shows that the
heat transfer increases with the increasing air pressure and it is found higher
for higher thermal conductive material. We also propose an analytical model
based on the normalized output voltage difference to extract the probe-sample
thermal contact resistance. The obtained Rc values in the range of ~1.8e7 K/W
to ~14.3e7 K/W validate the presented analytical model. Further analysis
reveals that the thermal contact resistance between the probe and sample
decreases with increasing air pressure. Such behavior is interpreted by the
contribution of heat transfer through confined air on thermal contact
resistance. In addition, the signature of Rc is also evidenced in the context
of thermal mismatch behavior which is studied by using acoustic mismatch model
(AMM) and diffuse mismatch model (DMM).
