In situ annealing studies of molecular-beam epitaxial growth of SrS:Cu

Annealing studies are reported on molecular-beam epitaxial grown SrS:Cu which has potential as a blue phosphor for full color electroluminescent (EL) displays. It was found that annealing under a sulfur flux at 650 °C greatly improved film quality and luminescent brightness. This was attributed to the reduction of sulfur vacancies, and a large enhancement in the grain size of these thin-film phosphors. Using this procedure, EL devices with a luminance of 26 cd/m² at 40 V above the turn-on threshold voltage with chromaticity coordinates of $\text{x=0.17,}$ $\text{y=0.29}$ were obtained.