Size-dependent thermal diffusivity of multilayered thin films deposited on substrates characterized by transient grating technique

摘要

The thermal diffusivities of bilayered thin films with nanoscaled thickness deposited on substrates are characterized by nanosecond transient grating method. Based on the transient grating experiment, two-dimensional thermal diffusivity model and eigenfunction expansion method are used to calculate the thermal fields in the trilayered structures. By fitting the theoretical calculations to the experimental data of a series of trilayered structures Al/ZnO/Si with different thicknesses of ZnO films, the thermal diffusivities of the Al and ZnO films can be evaluated simultaneously. The results show that the thermal diffusivities of the ZnO films are size dependent and increase with thickness of the films.