Thermal conductivity of CVD diamond at elevated temperatures

Transient thermal grating and laser flash techniques have been used to measure in-plane (k∣∣) and perpendicular (k⊥) thermal conductivity of 0.3-0.6 mm thick polycrystalline MPCVD diamond films. A small (<20% ) anisotropy in k is revealed, and a correlation of k (8-20 W/cm K at RT) with optical absorption and hydrogen impurity concentration is established. The temperature dependence k(T) between 293 and 460 K follows the relationship k∼T−n (n=0.17-1.02) depending on the diamond quality.