Measurement of charge carrier dynamics in diamond thin films using a fast TOF system with a UV pulsed laser

Charge carrier dynamics in CVD homoepitaxial diamond thin films were evaluated. Thicknesses of these thin diamond films were 4.5–14 μm. Measurement was carried out using a fast TOF system with time resolution of 150 ps. This system adopted the localized irradiation mechanism of a 213-nm UV pulsed laser. Induced current caused by charge carrier motion was simulated by a one-dimensional approximation. Then measured signals were analyzed using the physical model of induced current that was confirmed through the simulation. The best lifetimes, τ, of electrons and holes in evaluated diamond films were 1.8 ± 0.3 ns for both charge carriers. However, drift velocities and mean free paths of trapping were not determined because insufficient charge carriers arrived at the further side electrode without trapping.