Nanocrystalline Diamond Film on Large Area Glass Substrate

A high quality, transparent, smooth nanocrystalline diamond film was successfully grown on a Pyrex glass substrate by the microwave plasma chemical vapor deposition (MWPCVD) method. The deposition was carried out using a CH4/H2 plasma maintaining the substrate temperature at as low as 500 C. The films are smooth and reasonably uniform over an area of 30 x 30 sq cm and exhibit strong adhesion to the glass substrate. UV Raman spectroscopy (244 nm excitation wavelength) shows a high quality diamond film by the sharp peak at 1333 /cm. X-ray diffraction analysis indicates that the film consists of nanocrystal diamond, i. e., the crystallites ranged in size from 10 to 20 nm. The transmittance for visible light of a film with a thickness of approximately 1 micron is 55 % at a wavelength of 500 nm and is greater for higher wavelength, reaching 80 % at 766 nm. This high transmittance in the visible light region makes it possible to coat glass windows with diamond film for use in abrasive or other extreme environments, possibly replacing the more expensive materials currently in use.