Thermal Conduction Measurements of Diamond Thin films by Time Domain Thermo Reflectance Technique
| Autor: | Cheng, Hao-Yu, 鄭皓宇 |
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| Rok vydání: | 2015 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 103 Crystalline diamond possesses several fascinating properties such as high mechanical hardness, high thermal conductivity and low friction coefficient. However, diamond thin films do not always possess the same properties of crystalline diamond. It was demonstrated that the properties of diamond thin films vary a lot depending on the growth techniques and parameters. It is thus possible to optimize the properties of diamond thin films for particular applications. Diamond thin films were engineered at nanoscale by introducing H2 in the commonly used Ar/CH4 deposition plasma in a microwave plasma enhanced chemical vapor deposition (MPECVD) system. The presence of H2 influenced the granular structure of diamond films, resulting in different thermal properties. We utilized time domain thermoreflectance (TDTR) techniques to measure the thermal conductivities of diamond thin films deposited with different growth conditions. For TDTR measurement, all of diamond thin films were coated with an Al thin film as a transducer. After the optical pump pulses generated heat in the Al thin film, we monitored the time evolution of temperature near the surface of the Al film up to a few nanoseconds. We used a heat flow model to fit the TDTR traces and obtained the thermal conductivities of diamond thin films with different granular structures. The thicknesses of the diamond thin films were measured by scanning electron microscope (SEM). |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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