Ce3+ luminescent centres in atomic layer epitaxy SrS thin film electroluminescent devices

A luminescent study under selective photonic excitation has established the presence of three different kinds of Ce3+ centres in SrS atomic layer epit axy thin films: one in a regular sulfur octahedral sites and two others in lower symmetry. These last sites shift the emission spectra towards the gre en. High thermal annealing up to 750 degrees C improves the crystallinity o f the SrS:Ce layer by converting low symmetry Ce3+ sites in regular octahed ral sites and decreasing the density of defects. These two effects lead to efficient PL layers with a good blue chromaticity.