Effect of selective doping on photo- and electroluminescence efficiency in Si:Er structures

In this contribution we present the results on photo- and electroluminescence investigations performed in uniformly and selectively doped Si:Er structures. A series of a novel type of Si:Er structures, namely, periodically doped Si/Si:Er/Si/Si:Er.../Si structures varying by a number of Si/Si:Er periods and thickness of both Si:Er and Si layers were grown by the sublimation MBE method. A strong, by more than an order of magnitude, increase of photo- and electroluminescence efficiency at 1.54 mum was observed in these structures as compared to the uniformly doped ones. It was shown that the luminescence efficiency of the selectively Er doped structures strongly depends on the thickness and purity of intermediate Si layers and even at the thickness of Si layers of about 1.7 nm is 3 times that achieved in structures doped uniformly. We account it for the enhancement of excitation efficiency of Er ions stimulated by the exciton formation in intermediate Si layers.