White light emission from Eu-doped SiOC films

Bilayers consisting of two SiOC films doped with Eu at different concentrations have been synthesized by magnetron cosputtering. The proper choice of annealing temperature allows us to avoid Eu diffusion and clustering, so that each layer maintains its optical properties. Under these conditions, the bilayer allows us to take advantage of the dependence of the photoluminescence peak position on the Eu concentration, so that an intense white emission is obtained at room temperature. This finding constitutes relevant progress towards the realization of efficient Si-based white light sources, which can be of great interest for applications in photonics or solid-state lighting. (C) 2014 The Japan Society of Applied Physics