Abstract: The invention provides a method for the formation of silicon nanoparticles, in sizes that fluoresce, by electrodeposition of silicon material onto a non-reactive (with HF) metal (e.g., platinum) surface from a solution of silicate and HF or HF/H2O2. In an embodiment of the invention, a positively biased substrate with a platinum surface is immersed in a solution of sodium metasilicate in HF/H2O2, a current is drawn and a coating of silicon nanoparticles is formed on the platinum surface.

Abstract: In the invention, an electrochemical etching of crystalline germanium or a germanium alloy produces well-segregated chromatic clusters of nanoparticles. Distinct strong bands appear in the photoluminescence spectra under 350 nm excitation with the lowest peaks in wavelength identified to be at 430, 480, and 580 and 680-1100 nm. The material may be dispersed into a discrete set of luminescent nanoparticles of 1-3 nm in diameter, which may be prepared into colloids and reconstituted into films, crystals, etc.