摘要
A low hole injection efficiency for InGaN/GaN micro-light-emitting diodes(μLEDs) has become one of the main bottlenecks affecting the improvement of the external quantum efficiency(EQE) and the optical power. In this work, we propose and fabricate a polarization mismatched p-GaN/p-Al_(0.25)Ga_(0.75)N/p-GaN structure for 445 nm GaN-based μLEDs with the size of 40 × 40 μm^(2), which serves as the hole injection layer. The polarization-induced electric field in the p-GaN/p-Al_(0.25)Ga_(0.75)N/p-GaN structure provides holes with more energy and can facilitate the non-equilibrium holes to transport into the active region for radiative recombination. Meanwhile, a secondary etched mesa for μLEDs is also designed, which can effectively keep the holes apart from the defected region of the mesa sidewalls, and the surface nonradiative recombination can be suppressed. Therefore, the proposed μLED with the secondary etched mesa and the p-GaN/p-Al_(0.25)Ga_(0.75)N/p-GaN structure has the enhanced EQE and the improved optical power density when compared with the μLED without such designs.
作者
张一丹
楚春双
杭升
张勇辉
郑权
李青
毕文刚
张紫辉
Yidan Zhang;Chunshuang Chu;Sheng Hang;Yonghui Zhang;Quan Zheng;Qing Li;Wengang Bi;Zihui Zhang(State Key Laboratory of Reliability and Intelligence of Electrical Equipment,Hebei University of Technology,Tianjin 300401,China;School of Electronics and Information Engineering,Hebei University of Technology,Key Laboratory of Electronic Materials and Devices of Tianjin,Tianjin 300401,China;School of Electrical Engineering,Hebei University of Technology,Tianjin 300401,China.;State Key Engineering Center of Flat-Panel-Display Glass and Equipment,Shijiazhuang 050035,China)
基金
supported in part by the National Natural Science Foundation of China (Grant Nos.62074050 and 61975051)
Research Fund by State Key Laboratory of Reliability and Intelligence of Electrical Equipment,Hebei University of Technology (Grant Nos.EERI PI2020008 and EERI_PD2021012)
Joint Research Project for Tunghsu Group and Hebei University of Technology (Grant No.HI1909)。