Dual-wavelength flash Raman mapping method for measuring the thermal diffusivity of a single supported nanowire

Abstract

The heat dissipation of electronic devices has become an enormous challenge with the dramatic increasing of integrated transistors on a chip. Nanowires are viewed as promising materials for solving this problem. The accurate measurement of thermal diffusivity is a precondition for further applications. This paper presents a non-destructive method to measure the thermal diffusivity of a single supported nanowire, which is called dual-wavelength flash Raman (DFR) mapping method. This method has a 100 ps temporal resolution based on the minimum time delay between the heating and probing laser pulses and 50 nm spatial resolution based on the minimum step of the probing pulse. Compared with previously proposed concentric DFR method, the probing pulse can move along the nanwire length and the movable probing laser beam allowed temperature measurements at the most sensitive position,which improves the measurement accuracy by 50%. Moreover, instead of the normalizaiton temperature method in concentric DFR method, a temperature phase method was proposed for analyzing the temperature variation curves. The measurements on a single supported silicon nanowire verified the reliability of the DFR mapping method. One thousand virtual experiments showed that the uncertainty of this method can achieve ±5%.