Characteristics of GaN stripes grown by selective-area metalorganic chemical vapor deposition

Abstract

We report on the selective-area metalorganic chemical vapor deposition of GaN stripes in the size range of 50 to 125 urn and the characterization of the morphology, topography, and optical properties of these stripes. GaN films (∼1–3 μm) grown on (0001) sapphire are used as the substrates. Excellent surface morphology is achieved under optimized growth conditions which include a higher V/III ratio than broad area growth. It is found that, under certain growth conditions, (0001) terraces of ~5 µm in width develop at the edges of all stripes, independent of stripe size and orientation. The selectively grown GaN yields stronger band-edge emission than the “substrate” GaN which indicates an improvement in optical quality. However, the donor-acceptor pair recombination (or conduction band to acceptor transition) and yellow emission are also enhanced in certain areas of the stripes. The spatial correlation of these emission bands is established by cathodoluminescence wavelength imaging, and the origin of these emissions is speculated.