Non-contact T-type Raman method for measurement of thermophysical properties of micro-/nanowires

Rev Sci Instrum. 2019 Apr;90(4):044901. doi: 10.1063/1.5080728.

Abstract

A non-contact T-type Raman method was presented for characterizing the thermophysical properties of individual micro-/nanowires, using a suspended sample-attached T-type sensor. The sensor wire's thermal diffusivity was determined by the laser flash Raman spectroscopy method, which directly extracts the thermal diffusivity (α) by comparing the square pulse and continuous laser heating induced temperature rise. The test wire's thermal conductivity (λ) can be extracted by comparing the laser spot heating the sensor wire induced local temperature rise before and after the attachment of the test wire. This non-contact T-type method was verified by comparing the measured thermal conductivity of an individual 25 µm diameter Pt wire with the standard value and then applied in the thermal transport property characterization of an individual 17 µm diameter carbon fiber. Experimental results indicated that the thermal conductivity first increases and then decreases in the temperature range from 215 K to 470 K. In principle, the presented non-contact method is applicable to characterize any individual micro-/nanowires, even those without Raman spectra.