Silicon carbide nanocrystals produced by femtosecond laser pulses

Abstract

Ultrashort laser pulses provide an excellent dry and clean patterning technique in nanoscience for preparing quantum dots and quantum wires as well as depositing nanocrystalline grains of technologically important semiconductors. Here, we experimentally demonstrate the formation of silicon carbide (SiC) nanocrystals with wide size distribution (70–700nm) by irradiation of carbon layers deposited on silicon wafers with ultrashort laser pulses of 42fs pulse duration with 1kHz repetition rate. Surface morphology of the laser irradiated region monitored by scanning electron microscopy (SEM) exhibits nanocrystalline agglomerates of various size in the vicinity of ablated craters. Transmission electron microscopy (TEM) measurements show the occurrence of ~100nm size cubic and hexagonal SiC polytypes in addition to Si and amorphous silica nanoparticles. Independent sample diagnostics with Raman active phonon modes also indicates the formation and solidification of several SiC polytypes, which occur around the irradiated crater region. Further development of this laser-induced process and the accurate control of the laser pulse parameters can open new routes for preparing tailor-made SiC nanomaterials that have useful properties for electronic and biomedical applications.