The mechanisms of carbon nano-flake balls growth by laser ablation and microwave plasma chemical vapor deposition

The role of laser ablation (LA) for synthesis of carbon nano-flake balls (CNFBs) in microwave plasma chemical vapor deposition (MPCVD) has been investigated. In this article, a systematic study in frequency, speed, pulse width and processing time of LA were conducted in order to identify the role of LA and find an optimized condition window of the growth process. In addition, the study also demonstrates the nucleation and growth mechanism of CNFBs through Optical Emission Spectroscopy (OES), high-resolution transmission electron microscopy (HRTEM), and electron energy loss spectroscopy (EELS) observation on the spacing between graphite and diamond and the SiC interface between Si and diamond site. The defect areas, which are caused by H-alpha etching, react with carbon atoms to form a layer of SiC film, then followed by the increasing amount of CH and CN-C-2 radicals, forming diamond nanoparticle and graphite, respectively. In other words, the growth of CNFBs is the near simultaneity of the formation of diamond nanoparticle and the growth process (diamond and graphite). It is discovered that the existence of defects on the silicon substrate and the silicon carbide (SiC) layer after LA are the key factors of growing CNFBs.

Automated summary

This study investigates the role of laser ablation in the synthesis of carbon nano-flake balls in microwave plasma chemical vapor deposition. Through systematic studies, it is found that defects on the silicon substrate and the silicon carbide layer after laser ablation are key factors for the growth of CNFBs.