Our half-cavity photonic structure - nitride-based DBR - consists of alternating layers GaN and AlxGa1−xN. The advantage in using this type of DBRs is that the active layer, microcavity or light emitting elements, e.g. a quantum well or a quantum dot can be deposited in the same process used to deposit the layers for the DBR. This significantly simplifies the fabrication process of devices.
An optically ative layer emdedded in an optical cavity is GaN:(Mn, Mg). Co-doping with Mn and Mg with the concentration of both less than 1% results in the formation of robust cation complexes Mn-Mgk, responsible for a broad infra-red emission in the infra-red that covers two telecommunication windows, i.e. at 1.33 µm and 1.55 µm [1-2].
Figure 1: Transmission electron miscropy image of a DBR structure and a (0002) reciprocal space map with three peaks corresponding to 1 - GaN layers in DBR, 2 - AlGaN:Mn buffer and 3 - AlGaN:Mn layers in DBR .
Figure 2: (a) Measured and calculated reflectivity spetra of a sample with 20 Bragg pairs. (b) Low temperature photoluminescence measurements of a sample with an active layer GaN:(Mn,Mg) deposited directly on a buffer and on a 20-folded DBR structure. An intensity enhancement by a factor of five is observed .