Silicon nanocrystals synthesized from silicon tetrachloride using electron beam reduction reaction

Silicon nanocrystals (Si NCs) were synthesized by the electron beam reduction reaction (EBRR). Silicon tetrachloride (SiCl₄ ), isopropyl alcohol (IPA), and toluene were used as the silicon source, radical scavenger, and solvent, respectively. Three types of sample were prepared: from a solution of SiCl₄ and IPA under irradiation by an electron beam (e-beam) with energy, current, and dose of 1 MeV, 0.2 mA, and 300 kGy, respectively, and from the reactants (SiCl₄ -only or SiCl₄ + IPA) under no e-beam irradiation. New features in the ultraviolet–visible absorption and photoluminescence spectroscopies for the case of e-beam irradiation were attributed to the formation of the Si NCs, as confirmed by fast Fourier transform processed image in field-emission transmission electron microscopy analysis. The possibility of the formation of the Si NCs was also validated by the Gibbs free energy calculations of the proposed reaction mechanism for EBRR of the SiCl₄ precursor