Abstract: In contrast to previous approaches, the present inventors have discovered that diamond films can be grown by carbon CVT reactions occurring exclusively in the exothermic regime, where the lower temperature (<1500.degree.C.) conditions considerably simplify the equilibrium gas phase chemistry. Under these conditions of a small temperature gradient and short transport distance between the source and substrate, supersaturation of the gas phase with regard to graphite and diamond does not attain sufficiently high values to induce spontaneous homonucleation of graphite and diamond in the gas phase. With this process, temperatures as low as 680.degree.C. were found to be sufficient to induce the growth of continuous diamond films free of non-diamond allotropes.

Abstract: An optically transparent furnace (10) having a detection apparatus (29) with a pedestal (12) enclosed in an evacuated ampule (16) for growing a crystal (14) thereon. Temperature differential is provided by a source heater (20), a base heater (24) and a cold finger (26) such that material migrates from a polycrystalline source material (18) to grow the crystal (14). A quartz halogen lamp (32) projects a collimated beam (30) onto the crystal (14) and a reflected beam (34) is analyzed by a double monochromator and photomultiplier detection spectrometer (40) and the detected peak position (48) in the reflected energy spectrum (44) of the reflected beam (34) is interpreted to determine surface temperature of the crystal (14).