AlGaN-based deep ultraviolet light-emitting diodes grown on nano-patterned sapphire substrates with significant improvement in internal quantum efficiency

Publication date: 1 June 2014
Source:Journal of Crystal Growth, Volume 395
Author(s): Peng Dong , Jianchang Yan , Yun Zhang , Junxi Wang , Jianping Zeng , Chong Geng , Peipei Cong , Lili Sun , Tongbo Wei , Lixia Zhao , Qingfeng Yan , Chenguang He , Zhixin Qin , Jinmin Li
We report high-performance AlGaN-based deep ultraviolet light-emitting diodes grown on nano-patterned sapphire substrates (NPSS) using metal−organic chemical vapor deposition. By nanoscale epitaxial lateral overgrowth on NPSS, 4-μm AlN buffer layer has shown strain relaxation and a coalescence thickness of only 2.5μm. The full widths at half-maximum of X-ray diffraction (002) and (102) ω-scan rocking curves of AlN on NPSS are only 69.4 and 319.1arcsec. The threading dislocation density in AlGaN-based multi-quantum wells, which are grown on this AlN/NPSS template with a light-emitting wavelength at 283nm at room temperature, is reduced by 33% compared with that on flat sapphire substrate indicated by atomic force microscopy measurements, and the internal quantum efficiency increases from 30% to 43% revealed by temperature-dependent photoluminescent measurement.