Phosphor-free micro-pyramid InGaN-based white light-emitting diode with a high color rendering index on a β-Ga₂O₃...

We demonstrate the InGaN/GaN-based monolithic micro-pyramid white (MPW) vertical LED (VLED) grown on (-201)-oriented β-Ga₂O₃ substrate by selective area growth. The transmission electron microscopy (TEM) reveals an almost defect-free GaN pyramid structure on (10-11) sidewalls, including stacked dual-wavelength multi-quantum wells (MQWs). From the electroluminescence (EL) spectra of the fabricated MPW VLED, a white light emission with a high color rendering index (CRI) of 97.4 is achieved. Furthermore, the simulation shows that the light extraction efficiency (LEE) of the MPW VLED is at least 4 times higher compared with the conventional planar LED. These results show that the MPW VLED grown on β-Ga₂O₃ has great potential for highly efficient phosphor-free white light emission.