Direct measurement of CVD diamond film thermal conductivity by using photoacoustics

Photoacoustics (PA) is a type of photothermal effect and differs from the other one, known as the "mirage" effect, by the generation of thermal deflection waves as acoustic waves in a gas adjacent to the sample due to the modulated light absorption. We analyzed the feasibility of using PA for direct measurement of thermal conductivity of diamond films. The method was tested on two types of diamond polycrystalline films grown by chemical vapor deposition in plasma of direct current and microwave discharges. The thermal conductivity properties of the diamond films obtained are discussed by taking into account the Raman, photoluminescent, cathodoluminescent and other properties of these materials. The thermal conductivity values are shown to depend on polycrystalline diamond him structural characteristics that are defined by the conditions of the deposition. (C) 1998 Elsevier Science S.A. All rights reserved.