A serious of non-polar a-plane AlGaN-based multiple quantum wells (MQWs) were successfully grown on the semi-polar r-plane sapphire substrate with metal organic chemical vapor deposition technology. Intense MQWs-related emission peaks at an emission wavelength covered from 277-294 nm were observed based on the photoluminescence measurement. It was found that the employment of the trimethyl-aluminum (TMAl) flow duty-ratio modulation method which was developed based on the two-way pulsed-flows growth technique played a crucial role to control the Al composition of the non-polar a-plane AlGaN epi-layers. The non-polar a-plane AlGaN-based MQWs were deposited with the new developed TMAl flow duty-ratio modulation technique. Evident-3th order X-ray diffraction (XRD) satellite peak was observed from the high resolution-XRD measurement, proving the successful growth of non-polar a-plane AlGaN-based MQWs with abrupt hetero-interfaces.

The performance of non-polar AlGaN-based ultraviolet light-emitting diode (LED) with completely lattice-matched AlInGaN quantum barriers along the [1-100] m-direction were firstly proposed and intensively studied. The simulation results indicated that the internal quantum efficiency (IQE) of the non-polar AlGaN-based LED could be enhanced by 9.7% at an injection current of 350 mA with the introduction of AlInGaN barriers. Compared with the nonpolar AlGaN-based LED with conventional AlGaN quantum barriers, not only the Shockley–Read–Hall recombination rate for the nonpolar AlGaN-based LED with quaternary barriers was remarkably reduced, but also the radiative recombination rate was significantly improved. The enhanced performance for the nonpolar AlGaN-based LED with AlInGaN barriers could be interpreted as the result that the density of dislocations in active region was decreased due to the reduced in-plane strain in the AlGaN/AlInGaN MQWs.