The hot electron energy distribution function in ZnS:Cu:Cl:Er thin films

Co-evaporation in vacuuum is used to produce ZnS:Cu:Cl:Er thin films which give bright direct current electroluminescence at low voltages. Study of the electroluminescence emission intensities and the electroluminescence decay times of the rare earth centres shows that the hot electron energy distribution appears to follow a Boltzmann function, perhaps surprisingly in view of the low concentration of hot electrons involved. As would be expected, the mean energy of the hot electrons is found to increase, both with increasing applied voltage, and decreasing temperature of the thin film. (author)