Method and apparatus for characterizing spatially scanning dual-wavelength Raman flashes with substrate nanowires

Abstract

The invention discloses a space-scanning dual-wavelength Raman flash method and device for characterizing substrate nanowires, wherein the method includes: fixing a continuous heating laser at the center of a one-dimensional nanowire, heating the sample to a steady state, and heating the sample along the one-dimensional Change the position of the center of the continuous detection laser spot in the direction of the sample to obtain the temperature distribution along the length of the sample in a steady state; fix the pulse heating laser at the center of the one-dimensional nanowire, change the position of the center of the pulse detection laser spot along the direction of the one-dimensional sample, Measure the curve of temperature changing with time within a pulse period, calculate the phase at different positions, and obtain the distribution of the phase along the spatial direction; according to the temperature distribution of the steady-state process and the distribution of the phase of the transient process along the spatial direction, the fitting parameters can be obtained. physical parameters. The method can achieve the goals of non-contact, higher measurement accuracy and higher sensitivity through dual-beam non-co-point lasers, and is simple and easy to implement.

Description

technical field [0001] The invention relates to the technical field of thermal physical property testing at the micro-nano scale, in particular to a space-scanning dual-wavelength Raman flash method and device for characterizing substrate nanowires. Background technique [0002] Nanowires have broad application prospects in the field of microelectronics, thermoelectric conversion, photoelectric conversion and micro-nano sensors, and the premise of the application is to be able to accurately characterize the thermal properties of nanowires. In practical applications, nanowires rarely exist in the form of suspensions, and are usually placed on substrates. Due to the scale effect and the existence of interfaces, the thermophysical properties of nanomaterials and bulk materials, substrate nanomaterials and suspension nanomaterials show obvious differences. Therefore, it is of great significance to develop a simple and accurate thermophysical property measurement method for the m...

AI Technical Summary

Problems solved by technology

The 3ω method can be used to measure the thermal properties of platinum wire and carbon nanotube bundles, and this method has been used many times by researchers, but the disadvantage of this method is that it requires a definite linear relationship between the resistance of the wire to be measured and the temperature, and Passing an alternating current through the nanowires easily destroys the nanowires

The disadvantage of this method is that it is affected by the rising edge of the square wave pulse, the time resolution is difficult to improve, and the measurement accuracy is not high

Further, in the related art, the dual-wavelength Raman flash method is used to measure the thermal diffusivity of one-dimensional substrate nanomaterials, but this method relies on the accurate measurement of the temperature rise curve, and extremely small-scale materials such as carbon nanotubes The heating and cooling time of nanomaterials is extremely short, so it is difficult to accurately measure its temperature rise curve, and the measurement of the two laser beams at the same point cannot realize the detection at the position with the highest sensitivity, so the error is large and the sensitivity is low

[0005] In summary, the existing methods all have certain limitations, and it is difficult to accurately characterize the thermal properties of one-dimensional substrate nanowires. It is urgent to develop an accurate and simple in-situ measurement method

Images