The thermal conductivity of polycrystalline diamond films: Effects of isotope content

The thermal conductivities of two polycrystalline diamond films made by chemical-vapor-deposition process have been measured from a temperature of 15-550 K by using a standard steady-state technique. While one of the samples was of natural abundance composition (98.9% C-12 and 1.1% C-13) th, second sample was composed of 50% of each carbon isotope. Around room temperature the thermal conductivity of the natural abundant diamond film for heat flow parallel to the plane was found to be more than three times higher than that of the sample that contained equal amounts of each C-12 and C-13 isotopes. The results are interpreted in terms of the Klemens-Callaway model for thermal conductivity of solids as a function of temperature. (C) 1996 American Institute of Physics.