https://scholars.lib.ntu.edu.tw/handle/123456789/598387
標題: | High-quality AlGaN epitaxy on lattice-engineerable AlN template for high-power UVC light-emitting diodes | 作者: | Walde S Huang C.-Y Tsai C.-L Hsieh W.-H Fu Y.-K Hagedorn S Yen H.-W Lu T.-C Weyers M Huang C.-Y. HUNG-WEI YEN |
關鍵字: | Aluminum gallium nitride;Aluminum nitride;Edge dislocations;Electric resistance;Interface states;Lattice constants;Light emitting diodes;Semiconductor alloys;Strain;Current spreading;Forward voltage;High power;High quality;In-plane lattices;In-plane strains;Lightemitting diode;n-AlGaN;Strain state;Threading dislocation densities;III-V semiconductors | 公開日期: | 2022 | 卷: | 226 | 來源出版物: | Acta Materialia | 摘要: | AlGaN-based UVC light-emitting diodes (LED) were fabricated on high-quality AlN templates with an engineerable in-plane lattice constant. The controllability of the in-plane strain originated from the vacancy formation in Si-doped AlN (AlN:Si) and their interaction with edge dislocations. The strain state of the Si:AlN top interface could be well depicted by a dislocation-tilt model depending on the buffer strain state, threading dislocation density (TDD), and regrown Si:AlN thickness. The validity of the model was verified by cross-sectional TEM analysis. With a gradually widened lattice constant of regrown Si:AlN layer, strain-induced defects of subsequently grown n-AlGaN was suppressed. Therefore, growing a current spreading layer which possesses a moderate Al content (<65%), decent thickness (>1.5 ?m), and a low TDD (<1.0 × 109 cm?2) simultaneously becomes possible. Additionally, the idea of an optimal edge TDD (ρe,opt) in the AlN buffer was revealed for growing high-quality n-AlGaN layers with a targeted thickness. After a deliberate strain-TDD engineering for Si:AlN and n-AlGaN, high-power UVC LEDs (λ = 275 nm, P > 200 mW) with a low forward voltage (Vf = 5.7 volt) were demonstrated at I = 1.35 A. The low forward voltage under high current injection density was attributed to the success in preparation of a low series resistance and high-quality n-AlGaN current spreading layer. ? 2022 Acta Materialia Inc. |
URI: | https://www.scopus.com/inward/record.uri?eid=2-s2.0-85122631360&doi=10.1016%2fj.actamat.2022.117625&partnerID=40&md5=8ca2013467f0e4467eb7d4708aefedd0 https://scholars.lib.ntu.edu.tw/handle/123456789/598387 |
ISSN: | 13596454 | DOI: | 10.1016/j.actamat.2022.117625 |
顯示於: | 材料科學與工程學系 |
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