摘要
使用飞秒瞬态反射-透射技术研究了金和铜纳米薄膜的电子和晶格动力学,应用双温和Curde近似模型分析了金属薄膜的非平衡热传导动力学。假设在瞬态反射中电子-晶格耦合常数为常数的情况下,计算超快脉冲加热后的电子和晶格温度。金和铜纳米薄膜的反射和透射信号在初始2 ps内相似,随后时间里信号明显不同,透射模式下的电子-晶格耦合效应要比反射模式下的更强和更敏感。这是由于沿着膜厚方向的温度变化受到金属薄膜和基底间的界面散射影响造成的。在研究半透明薄膜的超快动力学过程中,需要同时考虑反射和透射情况。
The electron and lattice dynamics of gold and copper nanofilms are measured with femtosecond transient reflection and transmission techniques.Two-temperature model(TTM)and Crude-model approximation are applied to study the mechanism of heat transfer for metal nanofilms theoretically.Electron and lattice temperatures are calculated by TTM,which assume electron-lattice coupling coefficient as a constant for gold and copper.Compared the results of reflection with transmission,the difference of electron relaxation is negligible at the first two picoseconds,but electron-lattice coupling effect in the transmission method is stronger and more sensitive than that of the reflection method under the identical experimental conditions.Change of temperature gradient along with the direction of film thickness and electron-lattice coupling resistance due to the boundary scattering are responsible for the difference between transient reflection and transmission data.Both transient reflection and transmission of semitransparent films should be considered together for the investigation on the mechanism of ultrafast dynamics.
作者
吴文智
任世为
孔德贵
柴志军
WU Wen-Zhi;REN Shi-Wei;KONG De-Gui;CHAI Zhi-Jun(College of Electronic Engineering, Heilongjiang University, Harbin 150080, China)
出处
《黑龙江大学工程学报》
2021年第4期41-50,共10页
Journal of Engineering of Heilongjiang University
基金
国家自然科学基金面上项目(51773053)
黑龙江省留学归国人员科学基金项目(LC2017030)。
关键词
双温模型
电子-声子耦合
超快脉冲加热
基底效应
Crude模型近似
two-temperature model(TTM)
electron-lattice coupling
ultrafast pulsed laser heating
substrate effect
Crude-model approximation
