화학공학소재연구정보센터
Advanced Functional Materials, Vol.13, No.5, 412-417, 2003
Laser-induced direct lithography for patterning of carbon with sp(3) and sp(2) hybridization
A new method of laser-induced lithography for direct writing of carbon on a glass surface is described, in which deposition occurs from a transparent precursor solution. At the glass-solution interface where the laser spot is focused, a micro-explosion process takes place, leading to the deposition of pure carbon on the glass surface. Transmission electron microscopy (TEM) analysis shows two distinct co-existing phases. The dominant one shows a mottled morphology with diffraction typical of cubic (sp(3)) diamond. The other region shows an ordered array of graphene sheets with diffraction pattern typical of sp(2)-bonded carbon. The sp(3) crystallites range in size from 9 to 30 Angstrom and are scattered randomly throughout the sample. A UV Raman spectrum shows a broad band at the location of the expected diamond peak, together with a peak corresponding to the graphite region. We conclude that the patterned carbon is composed of a mixture of nanocrystalline sp and sp(2) carbon forms.