Evolution of surface morphology and optical transmittance of single crystal diamond film by epitaxial growth

The single crystal diamond (SCD) has great potential in the application of optical windows, photoelectric devices, semiconductors and other fields owing to its excellent performance in optics, mechanics, and thermotics. The SCD was homoepitaxially deposited on High Pressure and High Temperature (HPHT) seed substrate through microwave plasma chemical vapor deposition (MPCVD) method using CH4/H2 as the reaction gas. Hydrogen plasma treatment was proposed to pretreat the seed crystal. The top surface of the epitaxial layer of SCD has a creased morphology and no polycrystalline rim growth on the side. The results showed that the transmittance of the epitaxial SCD film was primarily affected by the surface roughness, which was mainly influenced by the growth time. The photoluminescence at 738 nm was attributed to the silicon color center in the grown SCD, suggesting the application in optoelectronic devices.