Mechanisms for the creation of intrinsic electron-hole trapping centers in a CaSO4 crystall

Abstract

The mechanism of creation of electron-hole trapping centers in CaSO4 at 15-300 K was investigated by the methods of vacuum-ultraviolet and thermoactivation spectroscopy. It is shown that electron-hole trapping centers are formed upon trap of electrons in the anionic complexes SO2−4 and localization of holes in the form of SO−4 radical. Based on the measurement of the spectrum of excitation of long-wavelength recombination emission at 3.0-3.1 eV and 2.7 eV, the energy distance of the formed electron-hole trapping centers was estimated (4.43 eV and 3.87 eV).

Keywords

• electron
• hole
• trap centers
• sulfates
• crystals
• luminescence