Silicon light emitting device based on rare earth oxide superlattice

A scalable, monolithic approach for rare earth based materials would open new opportunities for silicon photonics. High quality rare earth oxides can be epitaxially grown on silicon substrates (Smith et al., 2009). Crystallinity is key to making electrically pumped active media containing erbium (Er) as a major constituent. It is clear from previously published work in the field of silicon based photonics that incorporation of Er in a crystalline host allows active Er concentrations on the order of 10²² cm³ to be realized without segregation or secondary phase formation (Michael et al., 2008). Best performance is found to be for a material in which the Er is diluted as this avoids the problems of concentration quenching of optical processes such as photoluminescence. The material of choice for this work is therefore (Gd_1-xEr_x)₂O₃ in which Gd is the host material chosen because it has no optical transitions of its own in the wavelength range of interest. Figure [1a] shows the relationship between %Er and PL intensity, whilst figure [1b] shows the importance of the host rare earth comparing Yb with the final choice of Gd.