Accession Number : AD0286982

Title :   THE TRAPPING OF ELECTRONS AND HOLES IN MIXED CRYSTALS

Corporate Author : MASSACHUSETTS INST OF TECH CAMBRIDGE LAB FOR INSULATION RESEARCH

Personal Author(s) : MAYNARD,NELSON C.

Report Date : SEP 1962

Pagination or Media Count : 1

Abstract : Electrons and holes were produced in mixed crystals of KCl-KBr and KC L-RbCl solid solution systems by irradiation with 3-Mev electrons at -190, -80, and 20 C with doses 10 to the 5th power to 10 to the 6th power rads. The optical absorption resulting from the trapping of electrons and holes was measured by -190 C (liquidN temperature) to reduce bleaching. The mixed crystals of KCl-KBr and KCl-RbCl irradiated at liquid-N temperature contained F, F', K, and V sub 1 centers. The F and K centers appeared at -80 C while at 20 C irradiations, the F, K, and M bands were observed. The Mollwo relation is not valid for the shift of the maximum of all bands observed, possibly because of lattice distortion. The half-width of the F band is greater in mixed crystals. The V sub 1 band half-width in the KCl-RbCl system decreases contrary to that in KCl-KBr. Intensity of the F band-versus-composition curves for KCl-KBr exhibit both a relative maximum and a relative minimum, but in KCl-RbCl only a deep minimum. (Author)

Descriptors :   *COLOR CENTERS, *CRYSTALS, *ELECTRONS, *POTASSIUM COMPOUNDS, *RUBIDIUM COMPOUNDS, ABSORPTION, ALKALI METALS, BROMIDES, CHLORIDES, CRYSTAL LATTICES, ELECTRON BEAMS, GROWTH(PHYSIOLOGY), HALIDES, INTENSITY, LOW TEMPERATURE RESEARCH, OPTICAL ANALYSIS, SOLIDS, SOLUTIONS(MIXTURES)

Distribution Statement : APPROVED FOR PUBLIC RELEASE