Picosecond optical studies of amorphous diamond and diamondlike carbon: Thermal conductivity and longitudinal sound velocity

A picosecond pump-probe technique is used to measure the room-temperature thermal conductivity κ and longitudinal sound velocity cl of amorphous diamond (a-D) and diamondlike carbon (DLC) thin films. Both κ and cl were found to decrease with film hydrogen content. Depending on the film deposition technique, κ is in the range 5-10×10 -2 W cm-1 K-1 for a-D, and 3-10×10 -3 W cm-1 K-1 for DLC. Values of cl were found to be in the range 14-18×105 cm s-1 for a-D, and 6-9×105 cm s-1 for DLC.