Synthesis of Silicon Nanostructures: Comparative Study

Abstract

Silicon nanoparticles/nanostructures have been prepared by different methods. Lasers of different operational modes have been employed to prepare silicon nanoparticles by laser-induced etching, laser ablation and laser annealing. Moreover, electrochemical and photoelectrochemical etching were performed to synthesize silicon nanostructures. Optimum etching rate of 2.4 µm/min is obtained for the porous layer prepared by electrochemical etching under optimum conditions of 15 mA/cm2 and 10 minutes etching current density and etching time, respectively. Characterization of the prepared silicon nanostructures / nanoparticles was carried out using various methods. The experimentally observed Raman spectra of nanostructured layers prepared by three etching techniques reveal a red shift to 518 cm-1 and line broadening of 12 cm-1. While fitting of these spectra with the quantum confinement model provide an average size for nanostructured layers 6, 5.5 and 2 nm for photochemical, electrochemical and phooelectrochemical etching, respectively. The surface morphology investigation and their analysis provide valuable details on silicon nanostructure/nanoparticle size and size distribution.