Local Surface Modification of Quartz Glass by the Laser-Induced Reactive Deposition of Carbon Clusters

The surface of quartz glass was modified by the pulsed laser deposition of carbon clusters. A carbon target was irradiated by a pulsed laser transmitted through a quartz glass substrate to excite the carbon clusters deposited on the surface of the quartz. After continuous laser irradiation for several minutes, the resulting film on the irradiated spot (2 mm in diameter) was found to be optically transparent, but to exhibit electrical conductivity. The Raman spectrum of the irradiated region contained clear G and 2D band peaks, a likely sign of thin layers of graphite structures, but it also contained a D band peak originating from defects. The surface-modified regions were analyzed in detail using transmission electron microscopy and X-ray photoelectron spectroscopy. The analyses suggested that silicon carbide (SiC) generated by the laser-induced reaction between the carbon clusters and quartz substrate may have played an important role in the formation of the transparent conductive region on the surface of the quartz glass.