Electron irradiation and heat treatment of polycrystalline CVD diamond

Abstract
Photoluminescence and Raman spectra have been used to characterize the properties of diamond films grown by microwave plasma assisted chemical vapour deposition. Measurements at 77 K and excitation wavelengths in the range 476.5 nm to 514.5 nm show the presence of two components, A and B, in the Raman spectrum in addition to the diamond Raman line. The A and B components are rather similar in appearance and show resonant Raman behaviour. Electron irradiation results in the removal of the A and B Raman components, but they return to their original strength after after heating at 600 °C. The Raman scattering species interact with other point defects in the CVD films during heat treatment, and may be related to the presence of silicon in the diamond film.