Laser-Induced Chemical Vapor Deposition on Moving Glass Rods

The feasibility of using pyrolytic Laser-Induced Chemical Vapor Deposition (LCVD) to deposit carbon coatings on moving fused quartz rods have been investigated in this study. This LCVD system uses a CO₂ laser to locally heat substrates in open air to create a hot spot. Pyrolysis of hydrocarbon species occurs and subsequently deposits a layer of carbon film onto the substrate surface. The results of this study indicate that the deposition rate of carbon film increases exponentially within the range of laser power, while an increase in traverse velocity of the substrate will also increase the deposition rate until a maximum deposition rate is reached, and further increases in the traverse velocity will decrease the deposition rate. We suspect that this optimal deposition rate is caused by substrate motion, which affects the substrate surface temperature, and consequently the effective surface area available for film deposition.