Blue Emission Stimulation in Mixture of ZnO and Carbon Nanocrystals at Mechanical Processing

The photoluminescence (PL) and X ray diffraction (XRD) of the mixture of ZnO + xC nanoparticles have been studied before and after intensive mechanical processing (MP) with the aim to identify the native defects in ZnO nanocrystals (NCs). Three types of the ZnO + xC mixtures with the x equal to 0.1, 1.0 and 3.0 %wt have been investigated. The study reflects the diversity of physical and chemical processes occurring in samples during MP: the destruction of primary ZnO nanoparticle aggregates, crushing individual ZnO nanoparticles from the size of 250nm down to 14 nm, the development of pulse and accumulative thermal processes, the interaction of carbon atoms with oxygen in the treatment chamber and with the surface of ZnO nanoparticles etc. The new PL band peaked at 2.82-2.88 eV has been revealed in PL spectra after 9 min of MP. The origin of this emission in ZnO has not been conclusively established and a number of hypotheses have been proposed. Using carbon content variation in the studded ZnO + xC mixture the new PL band at 2.82-2.88 eV has been studded and its nature has been discussed.