Tunable silicon q-dots through ultrasonic milling

Silicon quantum dots (q-dots) 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 the dot dimensions. The ultrasound processes have been carried out in two different organic solvents (toluene and tetrahydrofuran) and allowed obtaining silicon q-dots emitting light in the blue-green part of the visible spectrum (estimated q-dots dimension around 5 nm). Moreover, by adding the proper chemicals in the solvents, such as alkenes, we have stabilized the q-dots achieving surface modification and observing an effect on size reduction. Photoluminescence spectra of the q-dots, TEM images and a preliminary micro-FTIR investigation of functionalised q-dots will be presented in this paper.