Effective Suppression of Surface Recombination of AlGaInP Light-Emitting Diodes by Sulfur Passivation

Jeng, Ming–Jer; Chang, Yuan-Hsiao; Chang, Liann‐Be; Huang, M.L.; Lin, Jia-Chuan

doi:10.1143/jjap.46.l291

Cited by 11 publications

(7 citation statements)

References 9 publications

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“…All TEM results in our experiments clearly indicate the surface recovery effect of chemical treatment to suppress surface defects such as a lattice disorder and the incorporation of impurities. All types of surface defects, such as lattice distortion and foreign atoms, are the most common cause of an SRH non-radiative recombination to generate different energy levels 13 , 28 . The SRH non-radiative recombination at the surface caused by defects is one reason for the decreased LED efficiency, particularly at a low current density 17 .…”

Section: Resultsmentioning

confidence: 99%

Enhancement in external quantum efficiency of AlGaInP red μ-LED using chemical solution treatment process

Jung

Lee

Kim

et al. 2021

Sci Rep

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To investigate the effects of their surface recovery and optical properties, extremely small sized (12 µm × 12 µm mesa area) red AlGaInP micro light emitting diodes ($$\upmu$$ μ LED) were fabricated using a diluted hydrofluoric acid (HF) surface etch treatment. After the chemical treatment, the external quantum efficiencies (EQEs) of $$\upmu$$ μ -LED at low and high injection current regions have been improved by 35.48% and 12.86%, respectively. The different phenomena of EQEs have a complex relationship between the suppression of non-radiative recombination originating from the etching damage of the surface and the improvement of light extraction of the sidewalls. The constant enhancement of EQE at a high injection current it is attributed to the expansion of the active region’s sidewall surface area by the selective etching of AlInP layers. The improved EQE at a low injection current is related to the minimization of the surface recombination caused by plasma damage from the surface. High-resolution transmission electron microscopy (HR-TEM) revealed physical defects on the sidewall surface, such as plasma-induced lattice disorder and impurity contamination damage, were eliminated using chemical treatment. This study suggests that chemical surface treatment using diluted HF acid can be an effective method for enhancing the $$\upmu$$ μ -LED performance.

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Section: Resultsmentioning

confidence: 99%

Enhancement in external quantum efficiency of AlGaInP red μ-LED using chemical solution treatment process

Jung

Lee

Kim

et al. 2021

Sci Rep

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“…These results highlight the necessity to optimize the process of MESA formation and passivation, in order to suppress the EQE drop by reducing the etching-related defects. In our case, the passivation involves the removal of the native oxide layer and the formation of a thin protective layer to prevent further atmospheric oxidation by using for example sulfur treatment with ammonium sulfide (NH4)Sx [34], [35]. Other techniques could be used such as plasma treatment [36], nitridation [37] or passivation with film deposition [38] such as ALD Al2O3 deposition [9], [29].…”

Section: Figure 12 Tof-sims Maps Of Chlorine and Boronmentioning

confidence: 99%

Investigation of sidewall damage induced by reactive ion etching on AlGaInP MESA for micro-LED application

Boussadi

Rochat

Barnes

et al. 2021

Journal of Luminescence

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Previous reports have studied the impact of sidewall defects on AlGaInP micro light emitting diode (µLED) only by Current-Voltage-Luminescence (I-V-L) measurements. In this work, we propose an alternative approach to investigate these defects directly after MESA formation, by coupling optical characterization techniques together with Time-of-flight secondary ion mass spectrometry (TOF-SIMS) on AlGaInP square shaped pixels of different sizes formed by BCl3-based Reactive Ion Etching (RIE). It is found that for a 6×6 µm² pixel, the light emission homogeneity is largely impacted by the sidewall defects. From emission efficiency map deduced by temperature-dependent cathodoluminescence measurements, we estimate that 86% of the 6×6 µm² pixel exhibit a lower efficiency than the center. The carriers lifetime extracted from time-resolved photoluminescence (TRPL) measurements on larger pixel begins to decrease gradually at 3 µm from the sidewall due to non-radiative recombinations. On the other hand, the TOF-SIMS analysis shows that residues of boron and chlorine remain on the surface and sidewalls of the pixel after BCl3 etching. These results show the importance to characterize the µLEDs at the MESA step and the necessity to optimize the etching process and the passivation.

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“…d) The peak EQE distribution of six different device sizes with and without sidewall treatment. [ 34 ] EL shift as a function of current density for e) 10 µm‐, f) 300 µm‐size LEDs. [ 17 ] Reproduced with permission.…”

Section: Size Dependence Of Electrical and Optical Performancementioning

confidence: 99%

“…[ 13,30 ] Additionally, potassium hydroxide [KOH] treatment was found to remove plasma‐damaged material, suppressing surface leakage currents. Thermal annealing followed by (NH 4 ) 2 S treatment was reported to completely remove the plasma damage in perforated LEDs [ 31–34 ] and N 2 plasma treatment recovered etch‐induced damage in n ‐type GaN. [ 35 ] Atomic‐layer deposition (ALD) sidewall passivation resulted in homogenous light emission at low current density and suppressed leakage current.…”

Section: Size Dependence Of Electrical and Optical Performancementioning

confidence: 99%

Micro‐Light Emitting Diode: From Chips to Applications

Parbrook

Corbett

Han

et al. 2021

Laser & Photonics Reviews

157

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Typical light‐emitting diodes (LEDs) have a form factor >(300 × 300) µm2. Such LEDs are commercially mature in illumination and ultralarge displays. However, recent LED research includes shrinking individual LED sizes from side lengths >300 µm to values <100 µm, leading to devices called micro‐LEDs. Their advent creates a number of exciting new application spaces. Here, a review of the principles and applications of micro‐LED technology is presented. In particular, the implications of reduced LED size in necessitating mitigation strategies for nonradiative device edge damage as well as the potential for higher drive current densities are discussed. The opportunities to integrate micro‐LEDs with electronics, and into large‐scale arrays, allow pixel addressable scalable integrated displays, while the small micro‐LED size is ideal for high‐speed modulation for visible light communication, and for integration into biological systems as part of optogenetic therapies.

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Effective Suppression of Surface Recombination of AlGaInP Light-Emitting Diodes by Sulfur Passivation

Cited by 11 publications

References 9 publications

Enhancement in external quantum efficiency of AlGaInP red μ-LED using chemical solution treatment process

Enhancement in external quantum efficiency of AlGaInP red μ-LED using chemical solution treatment process

Investigation of sidewall damage induced by reactive ion etching on AlGaInP MESA for micro-LED application

Micro‐Light Emitting Diode: From Chips to Applications

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