Near-field radiation analysis and thermal contact radius determination in the thermal conductivity measurement based on SThM open-loop system

With the rapid development of materials science, plenty of materials with micro-nano structures are emerging in various fields due to their outstanding physical properties. In order to fulfill the needs of micro-nano-scale thermal measurement, a series of thermophysical characterization methods have been evolving. In this article, a measurement method based on the Scanning Thermal Microscopy open-loop system is proposed to realize nano-scale thermal conductivity characterization. Both forward and backward thermal contact radius are measured. The heat transfer tunnel raised by the near-field radiation is calculated to be 1.73 × 10−14 W/K as the upper limit, which can be neglected compared to the total value. The total thermal conductance between tip and sample was calibrated as 1.8 × 10−6 W/K by several standard bulk samples, and thermal conductivity varies from 0.28 to 237 Wm−1 K−1.