Influence of thermal barriers on heat flow in high quality chemical vapor deposited diamond

Thermal barriers in high quality chemical vapor deposited (CVD) diamond were investigated by photothermal microscopy. High resolution measurements confirm that the in-plane heat transport is strongly limited by the presence of thermal barriers. Thermal resistances in the range of 10(-9) to 10(-8) m(2)K/W located at grain boundaries are extracted from photothermal line scans. Recently published data on macroscopic one-dimensional thermal transport in CVD diamond are well explained by the microscopic measurements in connection with a simple one-dimensional heat flow model.