CW laser‐initiated formation of nano‐Si crystals in glass‐metal nanostructures

Local and controllable growth of nanocrystalline silicon (nano‐Si) in a commercial borosilicate glass is demonstrated. The nano‐Si was formed in the subsurface region of the glass via aluminothermic reaction in the course of the irradiation of a 2D array of aluminum nanodisks fabricated on the glass surface with CW low‐power 633 and 532 nm lasers. The thermoplasmonic nature of the nanodisks heating is demonstrated: at low incident intensity, the phenomenon takes place only if the plasmon resonance of the array and the laser wavelength is close enough. However, when the laser beam intensity at the sample surface exceeds 8 MW/cm2 mutual position of the plasmon resonance and the laser wavelength weakly influences the phenomenon. The nano‐Si formation is studied with Raman scattering technique, and the average size of the silicon nanocrystals is evaluated.