Light-emitting silicon nanocrystals are prepared by the pyrolysis of silane and subsequent controlled size-reduction by chemical etching. These nanocrystals show luminescence tunable through the full visible spectral region. The luminescence rate increases by two orders of magnitude when shortening wavelength from red to blue side of the spectrum, which is interpreted as relaxation of the indirect band-gap energy structure. In addition we demonstrate a novel method to prepare regular arrays of nanospikes via deposition of suitable materials through the mask formed by a self-assembled monolayer of polystyrene beads. These structures could be used to improve light-emitting silicon devices and enable advancement on the way to true integrated silicon laser.