Fluorescent Rare Earths in Semiconducting Thiospinels

Abstract

The system CdS-In2S3-Tm2S3 has been investigated with the objective of obtaining for physical studies semiconducting crystals with high rare earth content. The new compounds CdR2S4 and CdR2Se4, where R represents the rare earths of small ionic size, have been found to have the spinel structure. Thulium was chosen as representative of this group of rare earths, and studies have been made largely in the pseudobinary system CdIn2S4-CdTm2S4, in which complete solid solution was found to occur. Both powder samples and single crystals have been prepared, and their lattice constants and infrared fluorescence measured. The structure of CdTm2S4 has been shown to be of the normal spinel type. Weak infrared electroluminescence from single crystals has been observed. © 1964, The Electrochemical Society, Inc. All rights reserved.