Broadband Ultraviolet Emission from 2D Arrays of AlGaN Microstructures Grown on the Patterned AlN Templates

Abstract

Broadband ultraviolet (UV) emission is achieved using AlGaN microstructure 2D arrays. 2D arrays of trenches are initially formed on AlN templates on sapphire (0001) substrates. AlGaN‐based quantum wells (QWs) are subsequently regrown on top of the patterned templates. Bunched steps are formed within the trench, inducing variations in the Al composition and AlGaN thickness in the QWs. Regions with and without bunched steps coexist and cause emission wavelength variations. The formation mechanism of bunched steps is attributed to the position‐dependent AlN growth rate due to variations of the source–precursor flow within narrow trenches.

Perspectives on UVC LED: Its Progress and Application

“…A chamfer angle of 4 • has also been reported to inhibit the growth of irregular grains at the interface [30]. When the substrate is arranged into a periodic concave-convex pattern, it can effectively inhibit the development of dislocations during the epitaxial growth process and annihilate them in the early stage of formation [31][32][33]. For instance, the group of Wang Junxi of the Institute of Semiconductors of the Chinese Academy of Sciences grew an AlN buffer layer on a patterned sapphire substrate, which enabled reducing the thickness of the buffer layer and improved the IQE of the UVC LED [34].…”