Synthesis and characterization of diamond microcrystals and nanorods deposited by hot cathode direct current plasma chemical vapor deposition method

(111) diamond microcrystals and (100) diamond microcrystals and nanorods were synthesized on Si substrate by hot cathode direct current plasma chemical vapor deposition method. The morphology, structure, and optical properties of the diamond films were characterized by scanning electron microscopy, X-ray diffraction, Raman spectra, and Fourier transform infrared spectra. The results showed that (111) and (100) diamond films can be grown under the condition of high-temperature (1223 K), low CH4 concentration (4/300 sccm) and low temperature (1098 K), high CH4 concentration (6/300 sccm), respectively. The (100) diamond film has lower purity and quality but higher optical transmittance than the (111) diamond film. Thus, the reactor temperature and CH4 concentration are responsible for the growth of diamond films.