Selective-area growth of GaN on non- and semi-polar bulk GaN substrates

We carried out the selective-area growth of GaN and fabricated InGaN/GaN MQWs on non- and semi-polar bulk GaN substrates by MOVPE. The differences in the GaN structures and the In incorporation of InGaN/GaN MQWs grown on non- and semi-polar GaN substrates were investigated. In the case of selective-area growth, different GaN structures were obtained on (20 (2) over bar1) GaN, (20 (2) over bar(1) over bar) GaN, and (10 (1) over bar0) GaN substrates. A repeating pattern of {1 (1) over bar 01} and {1 (1) over bar0 (1) over bar} facets appeared on (20 (2) over bar1) GaN. Then, we fabricated InGaN/GaN MQWs on the facet structures on (20 (2) over bar1) GaN. The emission properties characterized by cathodoluminescence were different for {1 (1) over bar 01} and {1 (1) over bar0 (1) over bar} facets. On the other hand, for InGaN/GaN MQWs on non- and semi-polar GaN substrates, steps along the a-axis were observed by AFM. In particular on (20 (2) over bar1) GaN, undulations and undulation bunching appeared. Photoluminescence characterization indicated that In incorporation increased with the off-angle from the m-plane and also depended on the polarity. (C) 2014 The Japan Society of Applied Physics