نبذة مختصرة : International audience ; In recent years, solid-state C-ultraviolet emitters (<230nm) have become an important issue for disinfection applications. AlN nanowire-based LEDs could prove to be a very serious option for this purpose. Here, the growth of AlN nanowires by plasma-assisted molecular beam epitaxy on in-plane ordered GaN pedestals is investigated. The influence of growth temperature and Al/active N ratio on the morphology of AlN nanowires puts in evidence the role of Al adatom diffusion length on both the top and the sidewalls. In addition, we found that the relative geometrical arrangement of Al effusion cell and N plasma cell with respect to sample normal drastically affects nanowire morphology, opening the path to the controlled formation of GaN/AlN core/shell nanowire heterostructures. Cathodoluminescence experiments reveal the correlation between near band edge optical signature and nanowire morphology, the sharpestband edge emission peaks corresponding to nanowires grown in migration enhanced epitaxy conditions.
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