Monolithically Integrating III‐Nitride Quantum Structure for Full‐Spectrum White LED via Bandgap Engineering Heteroepitaxial Growth

Abstract

AbstractGreat progress made by heteroepitaxial growth technology encourages rapid development of III‐nitride heteroepitaxial structures and their applications in extensive fields. Particularly, innate bandgap tunability of III‐nitride materials renders them attractive for white light‐emitting diodes (WLEDs) that are considered as next‐generation solid‐state lighting sources. However, commercial phosphor‐converted WLEDs suffer from poor color rendering index (CRI) and intense blue component, hard to fulfill demanding requirements simultaneously for energy efficiency and healthy lighting. Here, an efficient full‐spectrum WLED excited by monolithically integrated III‐nitride quantum structure is reported, in which trichromatic InGaN/GaN multiple quantum wells are constructed by bandgap engineering heteroepitaxy growth allowing flexible regulation of indium composition and quantum barrier thickness to manipulate carrier transport behavior. Furthermore, relationship between structural parameters and emission characteristics as well as their impact on white light performance is systematically demonstrated. Combined with commonly used green‐red phosphor mixture, the fabricated full‐spectrum warm/cold WLEDs can emit broadband and continuous spectra with low‐ratio blue component, first exhibiting superior CRI (> 97/98), color fidelity (97/97), saturation (100/99), and luminous efficacy (>120/140 lm W−1). This work demonstrates the advantages of bandgap‐engineered quantum structure applied in excitation source, and opens up new avenues for the exploration of high‐quality solid‐state lighting.