Colloidal blue and red luminescent silicon nanocrystals and their elaboration in pure and doped spin on glasses

Investigation of the surface chemistry of silicon nanocrystals (Si-ncs) in colloidal solutions is important to clarify factors involved in stability, luminescence efficiency and surface functionalization. We report on the photoluminescence (PL) properties of colloidal Si-ncs fabricated by two independent methods and elaborated in pure and phosphorous-doped spin on glasses (SOGs). Red luminescent Si-ncs were prepared by electrochemical etching and blue luminescent by nanosecond pulsed laser fragmentation of silicon micrograins. Our experimental results show that the PL maxima can be blue shifted within 40 nm with increase of phosphorous concentration in SOG matrix and a further blue shift (more than 250 nm) with efficient PL increase can be achieved by direct-nanosecond pulsed laser fragmentation of silicon micrograins in both pure and phosphorous-doped SOG colloidal solutions.