TY - JOUR
T1 - Stacking III-Nitride Ultraviolet-B Light Emitters with High Efficiency via a Lattice-Engineered Architecture
AU - Zhang, Ziyao
AU - Wang, Jiaming
AU - Xu, Fujun
AU - Zhang, Lisheng
AU - Lang, Jing
AU - Ji, Chengzhi
AU - Zhang, Junchuan
AU - Kang, Xiangning
AU - Qin, Zhixin
AU - Ju, Guangxu
AU - Yang, Xuelin
AU - Tang, Ning
AU - Wang, Xinqiang
AU - Ge, Weikun
AU - Shen, Bo
N1 - Publisher Copyright:
© 2025 Wiley-VCH GmbH.
PY - 2025/10/23
Y1 - 2025/10/23
N2 - AlGaN-based ultraviolet (UV) light emitters in the range of 280–320 nm (UVB band) show irreplaceable prospects in the field of medical care, but suffer from a low-efficiency issue known as the “UVB gap.” This issue stems from the large lattice mismatch between low-Al-content AlGaN and AlN, which causes the AlGaN epilayer to endure a significant compressive stress during structural stacking, resulting in dislocation multiplication and surface roughening, and thus seriously deteriorating the device performance. Herein, a lattice-engineered architecture through surface pretreatment is proposed, by which dense and discrete nanocrystalline graphite masks, formed by the decomposition of metal organics, are introduced to bring about controllable epitaxial lateral overgrowth and consequent stress. The stress in AlN is then continuously modulated from a compressive to a tensile state of 2.51 GPa with a strain of 0.51%, making its in-plane lattice constant equivalent to that of freestanding Al0.79Ga0.21N. As such, high-quality full-Al-content AlGaN epitaxy, in particular with an Al content below 50%, is realized, which brings about a significant performance improvement in 310-nm UVB LEDs, with a maximum wall-plug efficiency achieving 4.88%. This study makes a major breakthrough in the stacking of AlGaN-based UVB light emitters and definitely speeds up their further applications.
AB - AlGaN-based ultraviolet (UV) light emitters in the range of 280–320 nm (UVB band) show irreplaceable prospects in the field of medical care, but suffer from a low-efficiency issue known as the “UVB gap.” This issue stems from the large lattice mismatch between low-Al-content AlGaN and AlN, which causes the AlGaN epilayer to endure a significant compressive stress during structural stacking, resulting in dislocation multiplication and surface roughening, and thus seriously deteriorating the device performance. Herein, a lattice-engineered architecture through surface pretreatment is proposed, by which dense and discrete nanocrystalline graphite masks, formed by the decomposition of metal organics, are introduced to bring about controllable epitaxial lateral overgrowth and consequent stress. The stress in AlN is then continuously modulated from a compressive to a tensile state of 2.51 GPa with a strain of 0.51%, making its in-plane lattice constant equivalent to that of freestanding Al0.79Ga0.21N. As such, high-quality full-Al-content AlGaN epitaxy, in particular with an Al content below 50%, is realized, which brings about a significant performance improvement in 310-nm UVB LEDs, with a maximum wall-plug efficiency achieving 4.88%. This study makes a major breakthrough in the stacking of AlGaN-based UVB light emitters and definitely speeds up their further applications.
KW - AlN
KW - UVB LEDs
KW - nanocrystalline graphite masks
KW - tensile stress
KW - wall-plug efficiency
UR - https://www.scopus.com/pages/publications/105012403778
U2 - 10.1002/adma.202508380
DO - 10.1002/adma.202508380
M3 - Journal Article
AN - SCOPUS:105012403778
SN - 0935-9648
VL - 37
JO - Advanced Materials
JF - Advanced Materials
IS - 42
M1 - e08380
ER -