Formation and optical characteristics of AlGaN:Tb/GaN core–shell nanowires grown by organometallic vapor phase epitaxy

Abstract

We report the formation and optical/structural characteristics of Tb-doped AlGaN (AlGaN:Tb)/GaN core–shell NWs grown by organometallic vapor phase epitaxy. AlGaN:Tb layers are formed on GaN NWs in a core–shell configuration, as confirmed by cross-sectional transmission electron microscope equipped with energy dispersive x-ray spectroscopy (EDS). Tb3+-related visible photoluminescence (PL) is observed at room temperature simultaneously in the blue (∼490 nm), green (∼550 nm), yellow (∼580 nm), and red (∼620 nm) regions, which are assigned as the 5D4-7F6, 5D4-7F5, 5D4-7F4, and 5D4-7F3 transitions, respectively. The Tb luminescence intensity increases with the Al composition of the AlGaN host, exhibiting the strongest PL peak when Tb3+ ions are doped in the Al0.6Ga0.4N shell layers, whose AlN mole fraction is quantified by EDS elemental mapping.