Study of color centers in hot-filament CVD diamond films by cathodoluminescence and photoluminescence and their correlations with film quality

The color centers on the front and back of five free-standing diamond films grown by hot-filament CVD were characterized by cathodoluminescence and photoluminescence. The film quality was assessed by measuring the full width at half-maximum (FWHM) of the characteristic Raman diamond peak at 1332 cm(-1). A correlation between the color center luminescence and the film quality was derived. The cathodoluminescence study clearly showed that the intensities of band A and the 600 nm emission band increased with increasing quality. Conversely, the intensity of the 1.68 eV photoluminescence decreased as the film quality improved. The lower intensity of the 1.68 eV luminescence in higher quality films, observed in the samples grown in a silicon-free reactor, is different from the usual 1.681 eV luminescence from silicon-related centers, which shows a greater intensity in higher quality films.