Thermal resistance of thermal barriers in polycrystalline diamond
- Micrometer resolved photoțhermal measurements on chemical vapour deposited (CVD) diamond are presented. It is shown that the thermal conductivity inside the grains is as high as that of natural IIa diamond. Using two different approaches we measure the thermal resistance of thermal barriers like grain boundaries or microcracks and obtain values of the order of 10" m'Kw. A simple model is presented, relating the overall thermal conductivity for one-dimensional heat flow to the thermal resistance at barriers and the average size of the grains. Good agreernent between predictions and literature data is found, ...