Structural characterization of chemically synthesized CdSe nanoparticles

Analysis of the obtained data reveals the precipitation of defective zinc blende CdSe nanoparticles of size about 11 nm in diameter. A blue shift in the optical gap, from 1.71 to 1.82 eV, has been observed for the absorption spectrum of the synthesized CdSe nanoparticles, as an indication of quantum confinement effect. The zinc blende phase is enhanced upon annealing above the melting of Se (220 °C) as is transformed into a better order and stable wurtzite structure upon further heating. More than one melting point has been recorded for the CdSe nanoparticles referring to different ranges of particle sizes (7:25 nm). A value of 810 °C characterizes the melting point of the predominant size (11 nm) of the CdSe nanoparticles.