Transport of Nanoparticles in Afterglow Region Using Multi-Hollow Discharge Plasma CVD*

Plasma chemical vapor deposition (CVD) has attracted attention in nanoparticle synthesys because it is the dry process that can reduce impurity. It can control their coagulation by the charging of nanoparticles. So far, we have developed a multi-hollow discharge plasma CVD to produce size-controlled nanoparticles continuously using gas flow. Using the method, size-controlled Si and C nanoparticles were successfully produced [1-3]. Nanoparticles are nucleated and grow in the discharge region then transported toward the downstream region in which the substrates are set by gas flow. To realize bottom-up nanosystem fabrication, nanoparticle transport and deposition are important. Here, we have measured the amount of C nanoparticles (CNP) deposited on substrates as a parameter of the gap L between discharge and substrate to study the transport of CNP. The amount is proportional to the solid angle calculated from the L [3]. The result indicates the density of CNP is decreased as a function of L^-2 by their diffusion to the sidewall. 

[1] M. Shiratani et al., J. Phys. D Appl. Phys. 2011, 44, 1–8.

[2] S.H. Hwang et al., Plasma Fusion Res. 2019, 14, 1–5.

[3] S.H. Hwang, et al., Diam. Relat. Mater. 2020, 108050.