Systematic Raman spectroscopy for comprehensive measurement of thermal conductivity and optical properties of supported and suspended nanomaterials

Abstract

The invention discloses a system Raman spectrum method for comprehensively measuring the heat conduction and optical characteristics of nanometer materials with supports and suspensions. The system Raman spectrum method is suitable for non-contact in-situ comprehensive measurement of the heat conductivity and the heat diffusion rate of one-dimensional materials and two-dimensional materials in a base support and suspension state, the interface heat conduction between the nanometer materials and the supporting bases and the laser absorption coefficient. The system Raman spectrum method comprises the steps that a nanometer material sample is heated with continuous lasers and pulse lasers in sequence, and meanwhile the temperature is measured according to the temperature frequency shift characteristic of the Raman spectrum of the sample; the spot size of the continuous lasers and the pulse width of the pulse lasers are changed multiple times, and temperature rises measured under different spot sizes and pulse widths are compared, so that the laser absorption coefficient of the sample is eliminated, the heat conductivity, the heat diffusion rate and interface heat conductivity of the nanometer materials are extracted from the temperature rise ratio, and the laser absorption coefficient is measured on the basis. By means of the system Raman spectrum method, comparative measurement of heat conduction and optical characteristics of the same nanometer material sample in the state with the support and suspension can be achieved.

Description

technical field [0001] The invention belongs to the technical field of testing the thermal conductivity and optical properties of nanomaterials, and in particular relates to the thermal conductivity, thermal diffusivity, interface thermal conductance between nanomaterials and substrates, and the laser of nanomaterials in the state of substrate support and suspension Non-contact comprehensive measurement method of absorption coefficient. Background technique [0002] Nanoscale solid materials have great application potential in the fields of micro-nano electronics, micro-nano sensors, energy conversion, and medical equipment. In nanomaterials, heat transfer occurs in extremely small confined spaces, and the thermal conductivity characteristics are significantly different from those of macroscopic materials, and the analytical methods and testing methods used to characterize material properties at the macroscopic scale are no longer applicable at the nanoscale. Therefore, acc...

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Problems solved by technology

Contact measurement mainly has the following problems: (1) measurement is limited by nano-processing technology, and the process is complicated; (2) nano-samples are easily damaged during power-on measurement; (3) contact thermal resistance and contact resistance are difficult to avoid

Cai et al. further assumed that the laser absorption coefficient of graphene supported by a gold film is twice that of the suspension state, resulting in uncertainties in thermal conductivity and interface thermal resistance measurements as high as +176% / -86% and +57%, respectively. / -33%

The inability to accurately measure the amount of laser heating seriously affects the reliability of Raman spectroscopy in measuring the thermal conductivity of nanomaterials has formed a broad consensus

(2) The thermal diffusivity of suspended and supported nanomaterials cannot be measured, and there is no relevant report yet

(3) Lack of a complete thermal conduction model coupled with nanomaterials and substrates, it is difficult to accurately measure the thermal conductivity of nanomaterials supported by substrates

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