Some Effects of Low Fields on Luminescence of CdS

The effects produced on luminescence and conductivity in pure CdS crystals by application of electric fields up to ∼1000 v/cm are reported. A shift in the red and green cathodoluminescence peaks of ∼0.1 A/v/cm is observed. After application of the low fields, some crystals required over 90 minutes to recover their ``prefield'' luminescence. Fine structure in the luminescent peaks at room temperature is reported. A V-I plot shows a sublinear relation in this voltage range for several different levels of irradiation. An explanation of the observations is suggested based on self trapping of electrons.