240 nm AlGaN-based deep ultraviolet micro-LEDs:size effect versus edge effectOA北大核心CSTPCD
240 nm AlGaN-based micro-LEDs with different sizes are designed and fabricated.Then,the external quantum efficiency(EQE)and light extraction efficiency(LEE)are systematically investigated by comparing size and edge effects.Here,it is revealed that the peak optical output power increases by 81.83%with the size shrinking from 50.0 to 25.0μm.Thereinto,the LEE increases by 26.21%and the LEE enhancement mainly comes from the sidewall light extraction.Most notably,transversemagnetic(TM)mode light intensifies faster as the size shrinks due to the tilted mesa side-wall and Al reflector design.However,when it turns to 12.5μm sized micro-LEDs,the output power is lower than 25.0μm sized ones.The underlying mechanism is that even though protected by SiO2 passivation,the edge effect which leads to current leakage and Shockley-Read-Hall(SRH)recombination deteriorates rapidly with the size further shrinking.Moreover,the ratio of the p-contact area to mesa area is much lower,which deteriorates the p-type current spreading at the mesa edge.These findings show a role of thumb for the design of high efficiency micro-LEDs with wavelength below 250 nm,which will pave the way for wide applications of deep ultraviolet(DUV)micro-LEDs.
Shunpeng Lu;Jiangxiao Bai;Hongbo Li;Ke Jiang;Jianwei Ben;Shanli Zhang;Zi-Hui Zhang;Xiaojuan Sun;Dabing Li;
State Key Laboratory of Luminescence and Applications,Changchun Institute of Optics,Fine Mechanics and Physics,Chinese Academy of Sciences,Changchun 130033,China Center of Materials Science and Optoelectronics Engineering,University of Chinese Academy of Sciences,Beijing 100049,ChinaState Key Laboratory of Luminescence and Applications,Changchun Institute of Optics,Fine Mechanics and Physics,Chinese Academy of Sciences,Changchun 130033,China Key Laboratory of Electronic Materials and Devices of Tianjin,School of Electronics and Information Engineering,Hebei University of Technology,Tianjin 300401,China
电子信息工程
AlGaNdeep ultravioletmicro-LEDslight extraction efficiencysize effectedge effect
《Journal of Semiconductors》 2024 (001)
P.55-62 / 8
This work was supported by National Key R&D Program of China(2022YFB3605103);the National Natural Science Foundation of China(62204241,U22A2084,62121005,and 61827813);the Natural Science Foundation of Jilin Province(20230101345JC,20230101360JC,and 20230101107JC);the Youth Innovation Promotion Association of CAS(2023223);the Young Elite Scientist Sponsorship Program By CAST(YESS20200182);the CAS Talents Program(E30122E4M0).
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