Fig. 1. Optical microscope image of the mask pattern designed.

Fig. 2. (a) Top-view and (b) cross-section SEM images of InGaN/GaN MQWs grown on a GaN microring structure.

Fig. 3. (a) CL spectra from different facets of an InGaN/GaN MQW microring. Monochromatic CL intensity images over a single MQW microring at wavelengths of (b) 445 and (c) 560 nm.

Fig. 4. Position dependence of the CL peak wavelength from the inner {1-100} plane to the top (0001) surface.

Fig. 5. Photo image of EL at a 50 mA forward drive current for the fabricated LED chip wafer. The inset shows the surface pattern image of a single LED chip.

Fig. 6. EL spectra of white LED with increasing injection current. The inset shows the I–V characteristics of the LED.