Study On Thermal Characterization Of Solid Materials By MPR Technique

Modulated photothermal reflectance(MPR) technique is one ofmeasurement methods which are based on the photothermal effect. The MPR technique is a highly sensitive and nondestructive measurement method. Various applications of the technique have been developed over a wide range of science and technology. As a developing technique, however, the technique still needs not only to be developed to new fields, but also to be improved and consummated. This thesis mainly focuses on the development of the MPR technique applications. The main contents in this thesis are the following:In the first part, the theoretical and experimental studies of measuring thermal properties of bulk materials by MPR technique are performed. A new approach of measuring the thermal diffusivity for solid bulk materials is introduced. The experimental system is established and the new method is validated by corresponding experiments. It is shown that the method doesn't need to directly determine the sizes of pump and probe beams, which can effectively avoid the error resulted from the direct measurement of the pump and probe beam size. Moreover, the sample's thermal diffusivity is measured by MPR radial scanning methods. Experimental results are satisfactory.The theoretical study for characterizing thermal properties of thin films and substrates by MPR technique is present in the second part. A new method, MPR frequency scanning technique, is used to characterize the film-on-substrate system. The numerical multiparameter estimation is performed using the frequency response of MPR signals. Three thermal parameters, i.e. the film's thermal diffusivity, the substrate's thermal diffusivity and the thermal resistance on the film-substrate boundary, are simultaneously determined. It is shown that, comparing with the conventional MPR radial scanning method, there is no high correlation among the three thermal parameters in the MPR frequency model. Therefore the convergence and the accuracy of the multiparameter estimation can be improved by MPR frequency scanning method. On the other hand, MPR radial scanning signals of film samples with the low thermal diffusivity are analyzed in...