RAMAN AND PHOTOLUMINESCENCE SPECTRA OF AS-GROWN CVD DIAMOND FILMS

Emission spectra of diamond films grown by microwave-plasma-assisted CVD have been carried out at 77 K. The Raman spectra are not the same for different wavelengths of excitation. Deconvolution of these spectra shows two major components (A and B) in addition to the first-order diamond Raman line. The scattering cross sections of these components are large by comparison with the scattering cross section of diamond. The B component decreases in intensity with respect to the diamond Raman line as the wavelength of excitation is decreased. Component A is very similar to the spectrum from amorphous Si0.3C0.7:H by Ramsteiner and co-workers. It is suggested that the B component may be associated with a silicon-rich form of amorphous silicon carbide. There is a broad-band luminescence at 1.95 eV whose excitation behaviour and temperature dependence is similar to that associated with donor-acceptor recombination radiation in amorphous Si0.3C0.7:H as reported by Sussmann and co-workers.