摘要
考虑空间尺度对声子群速度的影响,采用Callaway热导率模型计算了单晶硅纳米线的品格热导率,讨论了三声子Umklapp过程、电子-声子散射、缺陷-声子散射以及边界-声子散射对热导率的影响.结果表明,纳米线的热导率比体材料小一个数量级,与不考虑受限声子群速度的结果相比,和实验符合得更好。另外,边界散射使得高温区的热导率体现出与温度几乎无关的特性.
Incorporating the size effect on phonon group velocity, the Callaway＇s model was utilized to analyze, the lattice thermal conductivity of a single-crystalline silicon nanowire. The theoretical results show that the thermal conductivity of silicon nanowire is one-magnitude lower than that of bulk silicon at 300 K. Comparing with the results in absence of modified phonon group velocity, better agreement with the experimental data can be achieved. In view of the dominated phonon-boundary scattering at high temperatures, the thermal conductivity is weakly associated with the temperature.
出处
《工程热物理学报》
EI
CAS
CSCD
北大核心
2008年第3期473-475,共3页
Journal of Engineering Thermophysics
基金
国家自然科学基金资助项目(No．50676046；No．50730006)
关键词
硅纳米线
热导率
色散关系
边界散射
silicon nanowire
thermal conductivity
phonon dispersion
boundary scattering
