Effect of Bi Doping on the Optical Properties of CdI2

Abstract

The effect of Bi impurity on the optical absorption and roentgeno-, photo-, and thermoluminescence spectra of CdI 2 crystals grown by the Bridgman-Stockbarger method is studied. CdI 2 activation with BiI 3 produces a number of absorption bands related to electronic transitions of Bi 3+ . Bi produces no emission centers in CdI 2 . The 550-to 560-nm luminescence of CdI 2 is due to the radiative recombination of self-trapped anion excitons. The observed changes in spectral distribution and the reduction in light yield upon CdI 2 activation with Bi 3+ are mainly due to the reabsorption of emission from native centers by activator centers. Under x-ray excitation, CdI 2 :Bi 3+ accumulates a small light sum at shallow trap levels related to native defects.

Calculations of structural, elastic, electronic, and optical properties of trigonal CdI2

“…The ionic cores are represented by ultrasoft pseudopotentials for Cd and I atoms. The Cd 4d 10 , 5s 2 , and I 5s 2 , 5p 5 electrons are explicitly 3 Results and discussion 3.1 Geometry and structure optimization The ground-state properties of trigonal CdI 2 are investigated and the total energy is fitted to the third-order Birch-Murnaghan equation [22] to obtain equilibrium lattice constants. The variation in the total energy as a function of volume is shown in Fig.…”

Studies of CdI2-Bi3 microstructures with optical methods, atomic force microscopy and positron annihilation spectroscopy

“…Due to peculiarities of the structural arrangement of CdI 2 there are specific ways of the incorporation of impurities or overstoichiometric Cd atoms into the crystal lattice. Therefore, a number of reports were devoted to the studies of doped CdI 2 crystals and crystals with excess of cadmium (see [2][3][4]). In particular, as demonstrated earlier [5], interesting changes in optical absorption are observed when CdI 2 is doped with BiI 3 (which is another layered compound).…”

Recombination processes in europium-doped cadmium iodide crystals

“…Activating or uncontrolled impurities caused the observed slight shift of the TSL peak maxima. The nature of the trapping centers responsible for the separate TSL peaks of the CdI 2 crystals has been discussed [30][31][32]. The experimental results and the literature indicated that the positions of separate peaks in the studied CdI 2 :Eu crystal phosphors and crystals based on CaF 2 [22,33] depended little on the cationic dopant.…”