Photoacoustic spectroscopy of annealed CdSxSe1-x (x = 0.26) nanocrystal doped glasses

Photoacoustic method has been applied to study the optical absorption properties of CdSxSe1-x (x=0.26) nanocrystals in a glass matrix annealed at 700 degrees C for different times. As the annealing time increases, the absorption peak in the PA spectra shifts to lower energies. The PA signal intensities exponentially decal below the fundamental absorption edges, of which the logarithmic dope increases with the increasing annealing time. It can be explained by decrease of the surface states relative to the whole electronic states due to the increase of radii and/or the increase of uniformity of the distribution of the nanocrystal sizes due to the annealing effect.