Effect of grain boundary angle on the thermal conductivity of nanostructured bicrystal ZnO based on the molecular dynamics simulation method. (December 2019)

• Record Type: Journal Article
• Authors: Liu, Yingguang; Bian, Yongqing; Chernatynskiy, Aleksandr; Han, Zhonghe
• Is Part Of: International journal of heat and mass transfer. Volume 145(2019)
• Publication Date: 2019-12
• Subjects: Grain boundary -- Kapitza resistance -- Thermal conductivity -- Phonon density of states; Heat -- Transmission -- Periodicals; Mass transfer -- Periodicals; Chaleur -- Transmission -- Périodiques; Transfert de masse -- Périodiques; Electronic journals; 621.4022
• DOI: 10.1016/j.ijheatmasstransfer.2019.118791
• Languages: English
• ISSNs: 0017-9310

Abstract

Highlights: The grain boundary (GB) energy and the Kaptiza resistance do not change monotonically with the angle when it exceeds 36°. Low-angle and high-angle GBs have a significantly different effect on Kaptiza resistance and thermal conductivity. Interpreting the influence mechanism of GB by comparing the phonon density of states at different GB angles. Abstract: ZnO is a widely used semiconductor material due to its excellent physical and mechanical properties. The thermal transport behavior across a single grain boundary (GB) of bicrystal ZnO with varying tilt angles from 5.45° to 67.38° was investigated using a nonequilibrium molecular dynamics simulation. The GB energy and Kapitza resistance as a function of tilt angle were determined and parameters of the extended Read-Shockley model were calculated. The Kapitza resistance varied monotonically with a GB angle <36° and was nearly constant when the angle was >36°. Furthermore, effective thermal conductivity and Kapitza resistance were found to depend strongly on the sample length and temperature. Finally, we compared the phonon density of states of the two types of GBs and found a mismatch in the low frequency that might explain the effect of the GBs structures on heat conduction.