Influence of silver clusters on the light absorption in CdBr2-Ag crystals

Experimental studies of the absorption spectra of CdBr2-Ag photochromic crystals revealed several absorption bands positioned close to the intrinsic absorption edge. It is suggested that impurity silver ions, neutral silver atoms and intrinsic lattice defects form nanoclusters which are responsible for the absorption peaks within the transparency range of the crystal. The effect of UV radiation on the absorption profile is also discussed in the framework of the proposed model

Long-term evolution of luminescent properties in CdI₂ crystals

Fresh and aged melt-grown or gas-phase grown CdI₂ crystals are studied by means of low-temperature photoluminescence spectroscopy. Noticeable transformations of emission spectra are observed after long-term aging. The formation of nanostructures containing cadmium oxide and cadmium hydroxide as well as the changes in local surrounding of iodine atoms and the possible growth of polytypic modifications of CdI₂ are taken into account when considering the diversity of optical spectra

Cadmium clusters in CdI2 layered crystals: the influence on the optical properties

The influence of overstoichiometric Cd i atoms on the optical properties of cadmium iodide layered crystals has been investigated. The results of optical absorption, luminescence, and luminescence excitation studies of CdI 2 crystals with controlled deviation from stoichiometric composition allow observing correlations between the Cd i concentration and features in absorption and emission spectra up to concentrations of 10 18 cm -3 . At higher concentrations the overstoichiometric cadmium atoms form clusters, which were observed using scanning electron microscopy. The extinction spectra of (CdI i ) n clusters are calculated in the frame of Mie theory and are found to correlate with the optical studies

Low-temperature luminescence of CdI2CdI_2 under synchrotron radiation

Synchrotron radiation is applied to study visible and UV luminescence spectra and their excitation spectra of undoped as well as In and Sb doped cadmium iodide crystals at 10 K. The origin of principal luminescence bands and the role of impurities in the formation of emission centers are discussed. The luminescence properties have been explained based on the electronic structure of CdI$_2$ crystals