Browsing by Author "Li, Xiaohang"

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Enhanced Optical Performance of AlGaN-Based Deep Ultraviolet Light-Emitting Diodes by Electrode Patterns Design
(2019-12-01)
Chen, Qian
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Dai, Jiangnan
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Li, Xiaohang
;
Gao, Yang
;
Long, Hanling
Low external quantum efficiency of deep ultraviolet light-emitting diodes (DUV LEDs) and current crowding can result in considerable heat generation, which has a great negative impact on device performance. In this paper, we investigate the influence of different electrode patterns on the photoelectric and thermal performance of DUV LEDs. We find that different electrode designs can achieve drastically different optical powers, with the superior design being the n-type electrode surrounding the active region. Moreover, compared with the counterpart, the superior design does not affect the electrical performance. The main reason is that the N-surrounding electrode pattern can provide enough current paths for carrier transport, thus realizing a more uniform current injection and can further improve the external quantum efficiency for DUV LEDs.
Ultraviolet polarized light emitting and detecting dual-functioning device based on nonpolar n-ZnO/i-ZnO/p-AlGaN heterojunction
(2019-04-15)
Dai, Jiangnan
;
Chen, Jingwen
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Li, Xiaohang
;
Zhang, Jun
;
Long, Hanling
We report on the demonstration of a 386 nm light emission and detection dual-functioning device based on nonpolar a-plane n-ZnO/i-ZnO/p-Al0.1Ga0.9N heterojunction under both forward and reverse bias. The electroluminescence intensity under reverse bias is significantly stronger than that under forward bias, facilitated by carrier tunneling when the valence band of p-AlGaN aligns with the conduction band of i-ZnO under reverse bias. Also amid reverse bias, the photodetection was observed and applied in a duplex optical communication device. Optical polarization of the light emission is studied for potential polarization-sensitive device applications. The proposed device provides an important pathway for the multifunctional devices operating in a UV spectrum. (C) 2019 Optical Society of America