Effect of Electron Bombardment on the Near-Infrared Fluorescence of Single-Crystal CdS

Under electron bombardment at 40°C, two fluorescence bands in the near infrared are observed in many CdS crystals. The bands are at about 8500 A and 1.05 μ. The 8500-A band is reduced in intensity by electron bombardment at 100 and 275 Kev and by exposure to x radiation. The 1.05−μ band is not greatly affected by these irradiations. Heat treatment for ½ hr at 200°C partially restores the 8500-A band. The effect is interpreted as a redistribution of electrons over the existing defects. The defect responsible for the 8500-A band is believed to be copper in a particular ionization state. The 1.05−μ band is observed to appear after heat treatment at 200°C if it is not present originally. This fact makes the origin of this latter band uncertain.