Excitation Mechanism of Electroluminescent ZnS Thin Films Doped with Rare-Earth Ions

Abstract

Electroluminescence(EL) and photoluminescence(PL) experiments have been carried out on the ZnS: Nd, ZnS: Cu, Cl and ZnS: Cu, Cl, Nd films. The EL emission spectra show two peaks due to Cu-Cl and Nd centers, while the PL emission spectra show only one peak due to Cu-Cl centers. By comparing the efficiencies and the emission spectra of the EL with the PL measurements, it has been clearly shown that the excitation mechanism of the Nd ions in the electroluminescent ZnS: Nd film is via direct impact excitation by hot electrons.