Development of high-quality semi-polar GaN for long wavelength emitters, Session 2: Growth II, Monday 30 January 2017
(11-22) semi-polar GaN is particularly important for achieving longer emission wavelength such as green and yellow emitters that have found wide applications in fabrication of phosphor-free white lighting sources, ultra-fast visible light communications (Li-Fi), polarized backlighting, and opto-genetics. However, semi-polar (11-22) GaN on industry-preferred substrates, such as sapphire, contains a high density of defects, including basal stacking faults (BSFs) and associated partial dislocations.
The Centre for GaN Materials and Devices has successfully obtained (11-22) GaN with significantly improved crystal quality on 2 inch sapphire by developing a cost-effective overgrowth approach on regularly-arrayed micro-rods, where the diameter, shape and orientation of micro-rods can be accurately controlled.
In his presentation on 30 January 2017, Professor Tao Wang demonstrated the high crystal quality (11-22) GaN/InGaN LEDs overgrown on such GaN templates, emitting strong green, yellow, yellow-green and amber emission. All the emissions demonstrate clear polarized features.