We report the structural, electrical, and optical properties of deep UV light emitting diodes (LEDs) grown by gas source molecular beam epitaxy with ammonia on sapphire and AlN/sapphire template substrates. AlN/ sapphire substrates were grown by stress controlled hydride vapor phase epitaxy (HVPE). LEDs based on n- and p-type AlN/Alx Ga1-xN (0.05 ≤ × ≤ 0.08) superlattices are demonstrated operating to wavelengths as short as 250 nm. We report a significant enhancement in the cathodoluminescence intensities (by factor of ∼100) and photoluminescence lifetimes in the Alx Ga1-xN/AlyGa1-yN superlattices consisting of well material grown in the three dimensional mode. We interpret these observations in terms of formation of quantum well/ quantum dot active regions.
|Number of pages||6|
|Journal||Journal of Materials Science: Materials in Electronics|
|State||Published - Sep 2008|