揭示热反射实验中热物性参数的本征关系  

Unraveling intrinsic relationship of thermal properties in thermoreflectance experiments

作　　者：陈韬 江普庆 Chen Tao;Jiang Pu-Qing(School of Energy and Power Engineering,Huazhong University of Science and Technology,Wuhan 430074,China)

机构地区：[1]华中科技大学能源与动力工程学院,武汉430074

出　　处：《物理学报》2024年第23期28-36,共9页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:52376058)资助的课题.

摘　　要：热反射技术是测量块体和薄膜材料热物性的重要工具,但参数间复杂的相互关系为数据解析带来挑战.本文以频域热反射法(FDTR)为例,利用奇异值分解(SVD)对热反射信号进行了深入分析,系统地揭示了不同变量之间的关联,并提出了热反射实验中的关键组合参数.这种方法不仅厘清了变量间的关系,还明确了实验中可提取的最大参数数量.作为应用实例,本文对铝/蓝宝石样品进行了测量和信号分析,发现相较于常规仅拟合衬底热导率和界面热导两个参数的做法,最佳拟合FDTR信号能够同时确定金属膜热导率、衬底热导率、衬底比热容和界面热导四个参数.拟合结果与文献参考值和其他方法测量结果进行了对比,验证了该方法的有效性.本研究深化了对热反射现象的理解,为热表征技术和材料研究的进一步发展提供了有力支持.Thermoreflectance techniques,particularly frequency-domain thermoreflectance(FDTR),play a crucial role in measuring the thermal properties of bulk and thin-film materials.These methods precisely measure thermal conductivity,specific heat capacity,and interfacial thermal conductance by analyzing the surface temperature response signals through thermoreflectance.However,the complex interplay among parameters presents challenges in data analysis,where single-variable analysis often fails to accurately capture intra-layer and interlayer interactions.In this work,FDTR is used as a case study and the relationships between sensitivity coefficients of various parameters are systematically explored through singular value decomposition(SVD).Specifically,the SVD of sensitivity matrix S of the system's parameters is performed to identify smaller singular values and their corresponding right singular vectors,which are the basis vectors of the null space of matrix S.These vectors reveal the relationships among parameter sensitivities,thereby uncovering the most fundamental combination parameters that determine the thermoreflectance signal.This method not only clarifies the dependency relationships between variables but also determines the maximum number of parameters that can be experimentally extracted,and the parameters that must be known beforehand.To demonstrate the practical value of these combination parameters,this work conducts a detailed analysis of FDTR signals from an aluminum/sapphire sample.Unlike traditional FDTR experiments,which typically fit only the thermal conductivity and interfacial thermal conductance of the substrate,our sensitivity analysis reveals that it is possible to simultaneously determine the thermal conductivity of the metal film,substrate’s thermal conductivity,substrate’s specific heat capacity,and interfacial thermal conductance.The fitting results are consistent with reference values from the literature and measurements from other thermoreflectance techniques,thus validating the effectiv

关 键 词：热反射 奇异值分解 热物性测量 反问题 

分 类 号：O551.3[理学—热学与物质分子运动论]