Size-Dependent Characterization of Deep UV Micro-Light-Emitting Diodes

Maclure, Daniel M.; McKendry, Jonathan J. D.; Herrnsdorf, Johannes; He, Xiangyu; Xie, Enyuan; Gu, Erdan; Dawson, Martin D.

doi:10.1109/ipc47351.2020.9252420

Cited by 6 publications

(4 citation statements)

References 5 publications

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“…24) To-date, the highest reported modulation bandwidth for a DUV LED is 570 MHz and was enabled by a single 20 μm diameter AlGaN micro-LED with a peak LOP of 130 μW. 25) Despite the reduced emission area for AlGaN-based micro-LEDs, the brightness (W cm -2 ) is remarkably enhanced due to their efficient light generation at kA cm -2 -level current densities enabled by a superior removal of the self-generated heat from the device active region. 21) At these levels of injection current density, the dynamic carrier lifetimes which chiefly dictate the maximum modulation bandwidth for micro-LEDs is also significantly reduced.…”

mentioning

confidence: 99%

Enhanced light extraction efficiency of micropixel geometry AlGaN DUV light-emitting diodes

Floyd

Gaevski

Hussain

et al. 2021

Appl. Phys. Express

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We report a 1.8 times improved light extraction efficiency for truncated cone AlGaN DUV (275 nm emission) micropixel LEDs when the pixel size was reduced from 90 to 5 μm. This is a direct consequence of reducing the re-absorption of sideways-travelling photons, as the lateral absorption length was measured to be 15 μm using cathodoluminescence. We also investigated the effect of an Al2O3/Al sidewall coating on the device performance which led to an on-wafer pulsed-mode brightness of 10.3 kW cm−2 from a single 5 μm truncated cone micropixel.

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mentioning

confidence: 99%

Enhanced light extraction efficiency of micropixel geometry AlGaN DUV light-emitting diodes

Floyd

Gaevski

Hussain

et al. 2021

Appl. Phys. Express

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“…A increases and then n(IQE peak) increases [28]. But the differences between the size-dependent J(EQE peak) are not large compared with the existing report [19], demonstrating the sidewall defect effect is not significant in this work. The wall-plug efficiency (WPE) versus current density for the UV-C LEDs are shown in figure 3(b).…”

Section: Resultsmentioning

confidence: 52%

“…In addition, the size effect on characteristics of UV-C micro-LEDs was also applied in deep-ultraviolet communications [17,18]. However, quantitative analyses and simulations of the mechanism for the size effect on efficiency and characteristics of UV-C micro-LEDs have not been adequately reported in literature, despite deserving far more research effort [19].…”

Section: Introductionmentioning

confidence: 99%

Analysis of the efficiency improvement of 273 nm AlGaN UV-C micro-LEDs

Qian¹,

Zhu²,

Shan³

et al. 2022

J. Phys. D: Appl. Phys.

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UV-C LEDs have great application prospects in the fields of sterilization, disinfection, and non-line-of-sight solar-blind communication. However, the efficiency is not high enough to satisfy the applications and needs to be improved. In this work, AlGaN based UV-C LEDs (273 nm) with size from 8 to 200 μm were fabricated to evaluate the size effect of external quantum efficiency (EQE). Higher EQE was detected in smaller-size UV-C micro-LEDs. Simulations on EQE were performed. The analysis on experimental data and the simulation results reveals that higher EQE originates from both higher internal quantum efficiency (IQE) at high current densities due to better current spreading and higher light extraction efficiency (LEE) due to larger proportion of the sidewall. From the efficiency improvement mechanism, it is concluded that the severer current density non-uniformity and LEE loss of UV-C devices compared with visible or near ultraviolet LEDs can be effectively restrained by preparing micro-LEDs. Our work helps to optimize the efficiency characteristics for UV-C applications.

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“…This has been attributed to smaller micro-LEDs being able to sustain higher operating current densities, in turn leading to shorter carrier recombination times and faster modulation responses. A size-dependent study on UVC micro-LEDs by Maclure et al [66] showed that this behavior is also observed in UV micro-LEDs. Fig.…”

Section: A Optical Communicationmentioning

confidence: 91%

AlGaN Ultraviolet Micro-LEDs

Tian

Shan

Zhu

et al. 2022

IEEE J. Quantum Electron.

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AlGaN-based UV LEDs have proven to have broad applications in many fields including sterilization, disinfection, purification, and phototherapy, but the performance still needs to be further improved. Benefiting from advantages such as better current spreading, lower self-heating effect and higher light extraction efficiency achieved by the reduced LED size, UV micro-LEDs are expected to improve quantum efficiency and thus can expand more potential applications. In this article, performance enhancement techniques and applications of UV micro-LEDs will be reviewed, providing an outlook for further development of AlGaN-based UV-LEDs. The micro-LED format offers possibilities to address fundamental issues that UV LEDs confront in general, but also demonstrates specific characteristics and performance advantages opening up new areas of application including high-speed optical communication, time-resolved fluorescence lifetime measurement, optical pumping, direct writing and charge management.

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Size-Dependent Characterization of Deep UV Micro-Light-Emitting Diodes

Cited by 6 publications

References 5 publications

Enhanced light extraction efficiency of micropixel geometry AlGaN DUV light-emitting diodes

Enhanced light extraction efficiency of micropixel geometry AlGaN DUV light-emitting diodes

Analysis of the efficiency improvement of 273 nm AlGaN UV-C micro-LEDs

AlGaN Ultraviolet Micro-LEDs

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