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Luminescent porous silicon (Psi) fabricated by simple chemical etching technique in different organic solvents was studied. By quantifying the silicon wafer piece, optical properties of the Psi in solutions were investigated. Observation shows that no photoluminescence light of Psi in all solvents is emitted. Morphology of Psi in different solvents indicates that the structure and distribution of Psi are differently observed. Particles are uniformly dispersive with the sizes around more or less 5–8 nm. The crystallographic plane and high crystalline nature of Psi is observed by selected area diffraction (SED) and XRD. Electronic properties of Psi in solutions are influenced due to the variation of quantity of wafer and nature of solvent. Influence in band gaps of Psi calculated by Tauc’s method is obtained due to change of absorption edge of Psi in solvents. PL intensities are observed to be depending on quantity of silicon wafer, etched cross-section area on wafer surface. Effects on emission peaks and bands of Psi under temperature annealing are observed. The spontaneous signals of Psi measured under high power Pico second laser 355 nm source are significant, influenced by the nature of solvent, pumped energy, and quantity of Si wafer piece used in etching process.

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In this article, luminescent Si nanocrystalline (NC) powder was uniformly dispersed in dimethyl sulphoxide and then incorporated into the SiO 2 gel matrix. Inorganic precursor tetraethylorthosilane was diluted in ethanol to form a homogenous solution. Dimethylformamide was used as a drying control chemical additive. Absorption and emission spectra of Si NPs in the silica gel with respect to time were recorded systematically at room temperature. The study reveals that the absorption and emission spectra of Si NPs, when doped in sol-gel silica matrix are modified. Influence in the band strengths and their peak positions upon ageing time are discussed. TEM shows existence of Si NPs of size ranges from 5 to 10 nm. Si NCs-doped sol-gel cylindrical rod was prepared and cut at different lengths from 10 to 15 mm to measure the optical gain. Photoluminescence stability of Si NCs in sol-gel is found for several weeks under the UV lamp.