Laser writing of glassy carbon features on Si from liquid toluene

Laser-assisted deposition from liquid phase is characterized by a high dens ity of precursors (up to 10(20) cm(-3)) and high deposition rates. The deco mposition of the precursor by a nanosecond laser pulse results not only in the deposition on the irradiated areas of the substrate, but also in the fo rmation of a dense suspension of clusters of the deposited materials in the bulk of the precursor solution. These clusters take part in the nucleation and growth of the deposited material inside the exposed areas of the subst rate. In the present paper, a copper vapor laser (wavelength of 510.6 nm, p ulse duration of 20 ns, repetition rate of 8 kHz) is used to deposit the mi crometer carbon features on a Si substrate immersed in liquid toluene. The carbon deposit is well-adherent to Si substrate and forms the ohmic contact . The deposition rate is 1-2 mu m s(-1) in laser writing mode and 0.3 mu m s(-1) in static irradiation. Raman analysis show that the deposit consists of glassy carbon with particle size of 4-5 nm. The cold emission of electro ns from the deposited features is studied as the function of experimental p arameters. Mapping the work function of the carbon deposit with a scanning tunnel field emission microscope (STFEM) shows that its maximum corresponds to the boundaries of larger grains of 20-30 nm in size. (C) 1999 Elsevier Science B.V. All rights reserved.