Laser writing of glassy carbon features on Si from liquid toluene

Laser-assisted deposition from liquid phase is characterized by a high density of precursors up to 1020 cmy3. and high deposition rates. The decomposition 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 formation 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 substrate. In the present paper, a copper vapor laser wavelength of 510.6 nm, pulse duration of 20 ns, repetition rate of 8 kHz. is used to deposit the micrometer 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 mm sy1 in laser writing mode and 0.3 mm sy1 in static irradiation. Raman analysis show that the deposit consists of glassy carbon with particle size of 4–5 nm. The cold emission of electrons from the deposited features is studied as the function of experimental parameters. 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. q1999 Elsevier Science B.V. All rights reserved.