Direct growth of patterned graphene on SiC(0001) surfaces by KrF excimer-laser irradiation

A novel method of direct growth of patterned graphene on SiC(0001) surfaces using KrF excimer-laser irradiation is proposed. It relies on the local sublimation of Si atoms within the irradiated area to induce graphene growth through a rearrangement of surplus carbon. A laser with a wavelength of 248 nm was pulsed with a duration of 55 ns and a repetition rate of 100 Hz that was used to graphene forming. Following laser irradiation of 1.2 J/cm(2) (5000 shots) under an Ar atmosphere (500 Pa), characteristic graphene peaks were observed in the Raman spectra of the irradiated area, thereby confirming the formation of graphene. The ratio between the graphene bands in the Raman spectra was used to estimate the grain size at 61.3 nm. Through high-resolution transmission electron microscopy, it was confirmed that two layers of graphene were indeed formed in the laser irradiated region. Using this knowledge, we also demonstrate that line-and-space (L&S) graphene patterns with a pitch of 8 mu m can be directly formed using our method.