InGaN-based epilayers and quantum wells with intense room-temperature photoluminescence in the 500-650 nm range

In,Ga1-xN epilayers (0 < x < 0.6) have been grown by plasma-assisted molecular beam epitaxy (PA MBE) on both c-sapphire via 0.8-mu m-thick GaN MBE buffers and 3-mu m-thick GaN MOVPE templates. Indium-incorporation efficiency in InGaN demonstrates a 5-10 times decay under the same conditions in the case of the MOVPE templates and is discussed in terms of thermodynamics (effects of growth temperature, N/III flux ratio, and composition) and kinetics (effects of surface step density, polarity). The InxGa1-xN/ InxGa1-yN multiple quantum well (QW) structures (0.3 < x < 0.55, 0 < y < 0.45) grown on the GaN MBE buffers, using a well controlled nitrogen flux modulation technique to change the composition and stoichiometry of the constituent layers, demonstrate intense room temperature photoluminescence in the 480-650 nm range, if the well is grown under the N-rich conditions and the barrier is under the group-III-rich ones. The effect seems to be caused by a 3D-growth-stimulated disordering of the In-rich InGaN alloy in the QW. (c) 2006 Elsevier B.V. All rights reserved.