Characteristics of surface and waveguide emitting SiGe: Er : O diodes

In this paper we demonstrate electroluminescence from erbium- and oxygen doped Si and SiGe diodes in surface emitting and waveguiding geometry. The layers were deposited by molecular beam epitaxy (MBE) on (1 0 0)Si. A series of samples with varying Er : O-doped layer thickness was grown, showing a decrease in luminescence intensity for layers thinner than 80 nm. The current-voltage characteristics and luminescence properties of another series of samples with varying Ge content were examined. They are probably influenced by strain relaxation at large Ge content. Si/SiGe waveguides were processed and their emission was analyzed by a confocal microscope setup. The spatially narrow emission and the dependence of luminescence on waveguide length proved optical guiding of the erbium emission.