Broadband Ultraviolet Emission from 2D Arrays of AlGaN Microstructures Grown on the Patterned AlN Templates. Issue 7 (2nd December 2019) - Kataoka, Ken
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. Abstract : Semiconductor emitters inherently show single‐peak emissions determined by the bandgap, whereas current major ultraviolet (UV) light sources of Hg lamps show multiple peaks. Herein, multiple‐component UV emission is achieved from semiconducting AlGaN using 2D microstructure arrays. This achievement may promote the use of environmental‐friendly AlGaN‐based UV emitters as alternatives to Hg lamps.