We report structural and optical properties of AlxGa 1-xN (0.4 < x < 0.5)/AlyGa1-yN (0.6 < y ≤ 1) quantum structures grown by gas source molecular beam epitaxy with ammonia on (0001) sapphire substrates. The structures are designed for light emission at ∼ 280 nm. The AlxGa1-xN (0.4 < x < 0.5) well material was grown under two dimensional (2D), three dimensional (3D), and (2D+3D) conditions by the varying group-III/ammonia ratio. The formation of nanoscale islands, or quantum dots (QDs), in the wells grown in 3D and (2D+3D) modes was observed using transmission electron microscopy. Optical properties are investigated using room temperature cathodoluminescence and time-resolved photoluminescence. Systematic studies allow us to obtain well growth conditions to produce ∼ 60 fold intensity enhancement over purely two-dimensional structures. Under these conditions, corresponding to deposition ∼ 10 monolayers of well material, we obtain emission at ∼ 280 nm with narrowest line width and longest photoluminescence decay time.
|Number of pages||3|
|Journal||Physica Status Solidi (C) Current Topics in Solid State Physics|
|State||Published - 2008|
|Event||7th International Conference of Nitride Semiconductors, ICNS-7 - Las Vegas, NV, United States|
Duration: Sep 16 2007 → Sep 21 2007