单晶锗薄膜热导率的分子动力学模拟

采用非平衡分子动力学(NEMD)方法研究平均温度为400 K,厚度d=2.8288～11.315 nm的单晶锗薄膜法向的热导率.模拟结果表明,单晶锗薄膜热导率随薄膜厚度的增加以接近线性的规律增加,其数值明显低于同等温度下体态锗的试验值.当薄膜厚度一定时,单晶锗薄膜的热导率随温度增加变化幅度很小,与同体态锗热导率随温度的变化规律相比表现出明显的尺寸效应.

Molecular Dynamics Simulation of Thermal Conductivity of Monocrystal Germanium Thin Films

Non-equilibrium molecular dynamics (NEMD) method was used to simulate the thermal conductivity of monocrystal germanium thin films on the out-of plane. In the simulation, the thickness of the films ranged from 2.8288 to 11.315 nm and the average temperature was 400 K. The results of calculations demonstrate that the thermal conductivity of the monocrystal germanium thin film increases nearly linearly with increasing of the film thickness, which is remarkably lower than the corresponding experimental data of bulk germanium. For a given film thickness, the thermal conductivity of the nanometer thin film varies slightly with increasing of the temperature, and its size effect is significant comparing with the thermal conductivity of bulks.