Effect of substrate facets on homoepitaxial growth of diamonds during plasma-assisted hot filament chemical vapor deposition

In this report, the effect of substrate facets has been investigated during homoepitaxial growths of diamonds on polyhedral diamond grains in a plasma-assisted hot filament chemical vapor deposition (HFCVD) system. Homoepitaxial diamonds grown on the (100) planes present smooth surfaces, whereas textured surfaces form on the (111) facets, which is attributed to the different growth modes corresponding to the single-crystal substrate facets. With the accretion of the methane concentration in the gas supply, a few crystallites appear on the smooth growing surfaces of the (100) facets, and a change from (111) to (100) textured surface takes place on the (111) facets, showing that the variation of plasma vapor chemistry further significantly adjusts the homoepitaxy of diamonds. Photoluminescence spectroscopy investigations reveal that the 575-nm N–V peaks of the homoepitaxial grown layers on the (100) facets are much weaker than those of the (111) facets, demonstrating that there are less vacancies in the diamonds homoepitaxially grown from the (100) facets than the (111) ones.