摘要
Heat management at nanoscaleis a criticalissue across many areas of science and engineering,where the size effect of thermal properties plays an important role.We measure the transient thermoreflectance signals of thin metal films with thicknesses from 50 to 200nm by using the femtosecond laser pump and probe method,and the experimental data are combined with the parabolic two-step model to enable us to measure thermal conductivity of the thin metal films.The measurement results of Ni and Al films show that,in the thickness range from tens to hundreds of nanometer,the thermal conductivity increases with the increasing thicknesses of the films,which agrees well with the previous conclusions.
基金
Supported by the National Basic Research Program of China under Grant No 2012CB933200
the National Natural Science Foundation of China under Grant Nos 50876103 and 50806075.