| Zugriffsnummer | 13639 |
| Dokumenttyp | Buchartikel |
| Sprache | Englisch |
| Titel | Thermal transport in diamond |
| Autor(in); Institution |
Hartmann, Jürgen; 7.21, Temperaturstrahlung, PTB-Berlin
Reichling, Michael; Universität München, München, GERMANY
|
| Quelle/Jahr | Properties, growth and applications of diamond:(2001), 32 - 39 |
| Schriftenreihe | EMIS datareview series: 26 |
| Herausgeber(in) |
Nazaré, Maria Helena
|
| ISBN | 0-85296-785-3 |
| Verlag | London: INSPEC |
| Freie Schlagworte | Thermalconductivity diamond ; Wärmeleitfähigkeit, Diamant |
| Zusammenfassung | One of the most outstanding physical properties of diamond is its extremely high thermal conductivity. This is exploited in advanced micro- and optoelectronic systems where diamond is integrated as a thermal management material, an application of growing importance since diamond is now available in form of high quality thin films. Room temperature thermal conductivity values up to 25 W/cmK have been reported for the highest quality single crystals of type IIa. This is the highest value of all known materials and exceeds that of copper, which is commonly regarded as an excellent thermal conductor, by a factor of more than six. In contrast to a metal, where thermal conductivity is provided by the mobility of conduction band electrons, heat transfer in the insulator diamond is solely carried by lattice vibrations, i.e. phonons. The reason for the outstanding thermal conductivity and the high Debye-temperature of 2000 K of diamond is the stiffness of the sp3 bonds forming its rigid structure together with the low mass of the carbon atoms. In most applications, the temperature is well below the Debye temperature and, hence, phonon-phonon scattering is small, resulting in little impedance for the phonon mediated heat transport in a large high purity crystal. Extrinsic phonon scattering mechanisms are the main source of thermal resistance in less pure material. For single crystal diamond, scattering at the sample's boundaries, at impurities and vacancies are the main contributions. For polycrystalline material, additional contributions arise from scattering at grain boundaries, dislocations and extended defects. All contributions influencing thermal conductivity depend on the wavelength of the contributing phonons and, therefore, on the temperature of the sample. Hence, for understanding phonon scattering mechanisms and their relative contributions, measurements of the temperature dependent thermal conductivity are of basic importance |
