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异质结构界面热输运的性能决定微纳米器件工作的可靠性. 本文采用分子动力学方法, 研究石墨烯/GaN三明治结构异质界面的热输运特性, 分析温度、缺陷以及尺寸对异质结构界面热导的影响. 研究发现, 随着温度的升高, 界面热导增大; 当温度为1100 K时, 3层石墨烯异质结构的界面热导增大61%, 分析认为这主要是温度升高导致晶格振动增加, 进而激发更多的平面外声子. GaN中的少量空位缺陷导致界面热导增大, 当缺陷率为20%时, 界面热导达到最大值0.0357 GW/(m 2·K), 分析认为缺陷会增加额外的热输运通道; 随后界面热导开始降低, 分析认为缺陷率增大导致界面耦合强度降低. 随着GaN层数从8层增加到24层, 界面热导下降, 计算声子模态发现参与界面热输运声子数量减少; 而石墨烯从2层到6层时, 界面热导先上升后下降, 分析认为这是与声子匹配和耦合强度的初期提高和后期声子散射及局部化增加有关. 该研究结果为调控微电子器件界面热输运提供理论依据.The performance of interfacial thermal transport in heterostructure determines the reliability of micro- and nano-scale device. In this study, a molecular dynamics method is used to investigate the interfacial thermal transport properties of graphene/GaN sandwich heterostructure. The effects of temperature, defect, and size on the interface thermal conductance at the heterostructure are analyzed. It is found that the interface thermal conductance increases with temperature rising; at 1100 K, the interface thermal conductance of the 3-layer graphene heterostructure is increased by 61%. This increase is mainly attributed to the enhanced lattice vibrations at higher temperature, which excites more out-of-plane phonons. The presence of minor vacancy defects in GaN leads interface thermal conductance to increase, reaching a maximum value of 0.0357 GW/(m 2·K) at a defect rate of 20%. This enhancement is believed to be due to additional thermal transport pathways created by the defects. However, as the defect rate increases further, the interface thermal conductance begins to decrease, which is thought to be due to interfacial coupling strength decreasing. With the number of GaN layers increasing from 8 to 24, the interface thermal conductance decreases, the change is attributed to the decrease of the number of phonons participating in the thermal transport across the interface. Conversely, with the number of graphene layers increasing from 2 to 6, the interface thermal conductance initially increases and then decreases. This behavior is related to initial improvements of phonon matching and coupling strength, followed by the increase in phonon scattering and localization. The results of this study provide a theoretical basis for regulating the interfacial thermal transport in microelectronic devices.
[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] [21] [22] [23] [24] [25] [26] [27] [28] [29] [30] [31] -
[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] [21] [22] [23] [24] [25] [26] [27] [28] [29] [30] [31]
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