The diamond films and single diamond micro-crystals studied by micro-Raman spectroscopy

Diamond films and single diamond micro-crystals were deposited on a Si substrate with a hot filament chemical vapor deposition (HF CVD) method from methyl alcohol–hydrogen gas mixture. The Raman spectra of diamond micro-crystals have been measured as a function of the crystals size and their orientation. The diamond Raman line was found to become broader and weaker with decreasing crystal size. The observed result can be explained by crystal size effect but phonon confinement or strain effect can not be excluded. It was also observed that the Raman spectrum depends on crystal orientation. In general the full width at half maximum of the diamond line is broader for (1 1 1) than (1 0 0) diamond plane. For thick diamond film the in-depth profile analysis was performed using confocal Raman microscopy.