White-emitting oxidized silicon nanocrystals: Discontinuity in spectral development with reducing size

Abstract

Small oxidized silicon nanocrystals of average sizes below 3.5 nm are prepared using modified electrochemical etching of a silicon wafer. Modifications introduced in the etching procedure together with postetching treatment in H2O2 lead to a decrease in the nanocrystalline core size and also, to some extent, to changes in the surface oxide. The interplay between these two factors allows us to blueshift the photoluminescence (PL) spectrum from 680 down to 590 nm, which is accompanied by changes in PL dynamics. This continual development, however, stops at about 590 nm, below which abrupt switching to fast decaying blue emission band at about 430 nm was observed. Discontinuity of the spectral shift and possible relation between both bands are discussed.

Fluorescent sensor for Cr(VI) based in functionalized silicon quantum dots with dendrimers

“…The common bottom-up approaches are driven by chemical reactions developed from precursors with final reduction treatments [20,21], decompositions based in laser induced pyrolysis [22] or plasma induced thermolysis [23,24]. The usual top-down approaches may include physical methods, as the laser ablation [25,26], ballmilling [27,28] and chemical catalyzed etching [29,30].…”

Luminescent Devices Based on Silicon-Rich Dielectric Materials

“…In fact, it has been reported that a largely disordered system is expected when the size of Si-nps is between 1 and 2 nm. Thus, the small Si-nps are no longer crystalline but amorphous like, as also indicated by theoretical calculations [49,50]. Then, the dispersed Si atoms in the M30 ilms are preferentially arranged as very small Si-nps (E' δ ) and some defects like oxygen-deiciency center (ODC) and NBOHC as reported for thin SiOx ilms (<100 nm) [51].…”

Silicon nanocrystals as fast and efficient light emitters for optical gain

“…The prepared silicon nanocrystals with oxidized surface (SiNc:O) have the size of the crystalline core of about 2.5-3 nm [20]. Their photoluminescence (PL) is quite typical for SiNcs as shown in Fig.…”