MBE GROWTH AND PROPERTIES OF GAN ON GAN SIC SUBSTRATES/

Growth of III-V nitrides by molecular beam epitaxy (MBE) is being stud ied at NCSU using an r.f nitrogen plasma source. GaN/SiC substrates co nsisting of similar to 3 mu m thick GaN buffer layers grown on 6H-SiC wafers by MOVPE at Cree Research Inc. are being used as substrates in the MBE film growth experiments. The MBE-grown GaN films exhibit excel lent structural and optical properties-comparable to the best GaN film s grown by MOVPE-as determined from photoluminescence, X-ray diffracti on, and vertical-cross-section TEM micrographs. Mg and Si have been us ed as dopants for p-type and n-type layers, respectively. AlxGa1-xN fi lms (x similar to 0.06-0.08) and AlxGa1-xN/GaN multi-quantum-well stru ctures have been grown which display good optical properties. Light-em itting diodes based on double-heterostructures of AlxGa1-xN/GaN which emit violet light at similar to 400nm have also been demonstrated. Gro wth of GaN on LiGaO2 substrates is also reported for comparison. (C) 1 997 Elsevier Science Ltd.