Enhancing the optical and electrical properties of AlGaN ultraviolet-C micro-LED via a hybrid scheme of plasma and chemical treatment

Feng, Feng; Liu, Yibo; Zhang, Ke; Zhanghu, Mengyuan; Chan, Ka‐Wah; Xu, Ke; Kwok, Hoi‐Sing; Liu, Zhaojun

doi:10.1063/5.0123409

Cited by 18 publications

(13 citation statements)

References 33 publications

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“…Thus, the emission of the 100 µm 2 ‐µLEDs is strongly influenced by light extraction than that of the 400 µm 2 ‐µLEDs. [ 51–54 ] Taken together, the EQE of the 100 µm 2 ‐µLEDs decreases after TMAH treatment even though the IQE increases because the sidewall smoothening reduces the light extraction.…”

Section: Resultsmentioning

confidence: 99%

Impact of Sidewall Conditions on Internal Quantum Efficiency and Light Extraction Efficiency of Micro‐LEDs

Park

Pristovsek

Cai

et al. 2023

Advanced Optical Materials

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The sidewall condition is a key factor determining the performance of micro-light emitting diodes (μLEDs). In this study, we prepared equilateral triangular III-nitride blue μLEDs with exclusively m-plane sidewall surfaces to confirm the impact of sidewall conditions. It was found that inductively coupled plasma-reactive ion etching (ICP-RIE) caused surface damages to the sidewall and resulted in rough surface morphology. As confirmed by time-resolved photoluminescence (TRPL) and X-ray photoemission spectroscopy (XPS), tetramethylammonium hydroxide (TMAH) eliminated the etching damage and flattened the sidewall surface. After ICP-RIE, 100 µm 2 -micro-LEDs (µLEDs) yielded higher external quantum efficiency (EQE) than 400 µm 2 -µLEDs. However, after TMAH treatment, the peak EQE of 400 µm 2 -µLEDs increased by around 10% in the low current regime, whereas that of 100 µm 2 -µLEDs slightly decreased by around 3%. The EQE of the 100 µm 2 -µLED decreased after TMAH treatment although the internal quantum efficiency (IQE) increased. Further, the IQE of the 100 µm 2 -µLEDs before and after TMAH treatment was insignificant at temperatures below 150 K, above which it became considerable. Based on PL, XPS, scanning transmission electron microscopy, and scanning electron microscopy results, mechanisms for the size dependence of the EQE of µLEDs are explained in terms of non-radiative recombination rate and light extraction.

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Section: Resultsmentioning

confidence: 99%

Impact of Sidewall Conditions on Internal Quantum Efficiency and Light Extraction Efficiency of Micro‐LEDs

Park

Pristovsek

Cai

et al. 2023

Advanced Optical Materials

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“…To define the mesa area more accurately, silicon oxide is patterned by photoresist as a hard mask for mesa etching in the inductively coupled plasma (ICP). Tetramethylammonium hydroxide (TMAH) treatment is involved as a post-ICP course to reduce sidewall damages for a preferable radiative recombination rate (13). A thin Ni/Au current spreading layer is first e-beam evaporated on the p-GaN layer and rapidly thermal annealed at 550℃.…”

Section: Methodsmentioning

confidence: 99%

3.2: Elevating the Light Output Power Density of Scaling‐down AlGaN Ultraviolet‐C Micro‐LED

Feng

Liu

Zhang

et al. 2023

Symp Digest of Tech Papers

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Ultraviolet band‐C (UV‐C) micro‐light‐emitting diodes (Micro‐LEDs) with high optical power density are increasingly demanded in the utilization of sterilization, solar‐blind communications, and neuroscience for the robust structure and adjustable emission wavelength. In this work, AlGaN UV‐C Micro‐LEDs are fabricated and characterized in 5×5, 10×10, 20×20, 30×30, 50×50, 80×80, and 100×100 µm2. With pixel size scaling down, the smaller devices have the potential to emit more considerable light output power (LOP) density at the same injected current density. This LOP density sizing effect implies higher luminescence efficiencies on small‐sized UV‐C Micro‐LEDs, which could be widely adopted by the industry.

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“…[147] Furthermore, recent research efforts have spotlighted the UV-C micro-LEDs on the color-conversion displays by tristimulus QDs. [148] Benefiting from the high QD absorbance and separated color emission from the pumping [150] Size-dependent d) optical power and e) EQE of UV-C micro-LEDs under various injection current densities. [148] (a-c) Reproduced with permission.…”

Section: Qd Micro-ledmentioning

confidence: 99%

Microdisplays: Mini‐LED, Micro‐OLED, and Micro‐LED

Miao

Hsiao

Sheng

et al. 2023

Advanced Optical Materials

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The field of next‐generation microdisplays is flourishing. Relevant display technologies, such as mini‐light emission diodes (mini‐LEDs), micro‐organic light emission diodes (micro‐OLEDs), and micro‐light emission diodes (micro‐LEDs) are thus in the urgent stage of development. From this perspective, comprehensive and systematical analyzes are conducted for the aforesaid microdisplay configurations. A holistic view of microdisplay technologies is developed with the corresponding performance metrics, providing a path for miscellaneous scenarios. Among these scenarios, the applications in augmented reality (AR), virtual reality (VR), wearable devices, and head‐up displays (HUD) are currently attracting considerable attention for deeper human‐digital interactions. However, there is a multiplicity of obstacles and challenges hindering such development. Nevertheless, recent advances in microdisplay technologies hold tremendous promise for the paradigms of these applications, taking a leap forward for next‐generation microdisplays. This review presents perspectives, relevant materials, and the technology landscape for such ongoing display technologies, offering guidance on the design of advanced microdisplays.

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Enhancing the optical and electrical properties of AlGaN ultraviolet-C micro-LED via a hybrid scheme of plasma and chemical treatment

Cited by 18 publications

References 33 publications

Impact of Sidewall Conditions on Internal Quantum Efficiency and Light Extraction Efficiency of Micro‐LEDs

Impact of Sidewall Conditions on Internal Quantum Efficiency and Light Extraction Efficiency of Micro‐LEDs

3.2: Elevating the Light Output Power Density of Scaling‐down AlGaN Ultraviolet‐C Micro‐LED

Microdisplays: Mini‐LED, Micro‐OLED, and Micro‐LED

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