Preparation of tunable silicon q-dots through ultrasound.

Silicon quantum dots (QDs) have been prepared through ultrasound treatments of light-emitting porous silicon layers (PSL) electrochemically etched from a p(+) type crystalline silicon (c-Si). The sonication treatments allowed separating the porous fraction from the bulk of c-Si as well as to mechanically reduce their dimensions. The ultrasounds processes have been carried out in two different organic solvents (toluene and tetrahydrofuran), and allowed obtaining silicon QDs emitting light in the blue-green part of the visible spectrum (estimated QDs diameter around 5 nm). Moreover, by adding the proper chemicals in the solvents, such as alkenes, or simply paraffin oil, we have stabilized the QDs achieving surface modification and observed an effect on size reduction. Photoluminescence spectra of the QDs, TEM images and a preliminary micro-FTIR investigation of functionalised QDs will be presented in this paper.