POSSIBILITIES AND LIMITATIONS OF BLUE ELECTROLUMINESCENCE IN CAS-PB2-FILMS( THIN)

While CaS:Pb is already well known as an efficient UV/blue emitting ph otoluminescent phosphor, only preliminary results on its thin film ele ctroluminescence are available. Thin film electroluminescent devices w ith a CaS:Pb active layer were deposited by electron beam evaporation. It was found that both the activator concentration and the substrate temperature during deposition strongly influence the optical character istics. X-ray photoelectron spectroscopy was used to determine the com position of the layers, and tt-le spectral characteristics were compar ed with results from photoluminescence.