RELAXATION OF ELECTRONIC EXCITATIONS IN CSI CRYSTALS STUDIED BY SYNCHROTRON-RADIATION AND PULSED ELECTRONS

The luminescence properties of CsI crystals have been investigated usi ng a pulsed 300 keV electron beam, VUV photons from a bending magnet a nd soft X-ray synchrotron radiation from an undulator source. The emis sion spectra of CsI crystals in the temperature range 8-300 K, excited by photons of 55-500 eV, were investigated. The intrinsic self-trappe d exciton (STE) emissions at 3.7 and 4.3 eV were observed at 8 K, as w ell as the intrinsic 4.1 eV emission and some extrinsic emissions tit 300 K. The fast emission band (1.8-2.7 eV), observed by the electron b eam irradition of CsI at 80 K, is assigned to the transitions between Cs+ 5p cation subbands. (C) 1998 Elsevier Science Ltd. All rights rese rved.