Micro-photoluminescence to investigate lateral diffusion of charge carriers in InGaN/GaN MQWs

Becht, Conny; Binder, Michael; Galler, Bastian; Off, J.; Tauer, Maximilian; Gomez‐Iglesias, Alvaro; Wang, Heng; Straßburg, Martin; Schwarz, Ulrich

doi:10.1117/12.2608901

Cited by 3 publications

(3 citation statements)

References 11 publications

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“…For sample U (respectively, R), this would correspond to L d,U > 1.9 µm (resp., L d,R > 0.5 µm) at room temperature. One should note that large diffusion lengths (>1 µm) have been recently reported in high-quality InGaN/GaN QWs grown on GaN substrates [26,27]. Figure 4a,b display panchromatic CL images.…”

Section: Cathodoluminescence Measurementsmentioning

confidence: 82%

Investigation of the Impact of Point Defects in InGaN/GaN Quantum Wells with High Dislocation Densities

Lottigier,

Di Paola,

Alexander

et al. 2023

Nanomaterials

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In this work, we report on the efficiency of single InGaN/GaN quantum wells (QWs) grown on thin (<1 µm) GaN buffer layers on silicon (111) substrates exhibiting very high threading dislocation (TD) densities. Despite this high defect density, we show that QW emission efficiency significantly increases upon the insertion of an In-containing underlayer, whose role is to prevent the introduction of point defects during the growth of InGaN QWs. Hence, we demonstrate that point defects play a key role in limiting InGaN QW efficiency, even in samples where their density (2–3 × 109 cm−2) is much lower than that of TD (2–3 × 1010 cm−2). Time-resolved photoluminescence and cathodoluminescence studies confirm the prevalence of point defects over TDs in QW efficiency. Interestingly, TD terminations lead to the formation of independent domains for carriers, thanks to V-pits and step bunching phenomena.

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Section: Cathodoluminescence Measurementsmentioning

confidence: 82%

Investigation of the Impact of Point Defects in InGaN/GaN Quantum Wells with High Dislocation Densities

Lottigier,

Di Paola,

Alexander

et al. 2023

Nanomaterials

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“…Imaging was carried out in scanning transmission electron microscope (STEM) mode using a high-angle annular dark-field (HAADF) detector that exploits atomic-number (Z ) contrast. Finally, µ-EL and µ-PL characterizations were performed through a custom designed spectral resolved confocal microscope setup which is discussed more in detail in [26], [27], and [28].…”

Section: Methodsmentioning

confidence: 99%

V-Pits and Trench-Like Defects in High Periodicity MQWs GaN-Based Solar Cells: Extensive Electro-Optical Analysis

Nicoletto,

Caria,

Rampazzo

et al. 2024

IEEE Trans. Electron Devices

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By combining microscopy investigation, light-beam induced current (LBIC), microphotoluminescence (µ-PL), and micro-electroluminescence (µ-EL) characterization, we investigate the electrical and optical properties of V-pits and trench-like defects in highperiodicity InGaN/GaN multiple quantum wells (MQWs) solar cells. Experimental measurements indicate that V-pits and their complexes are preferential conductive paths under reverse and forward bias. Spectral analysis shows a redshifted wavelength contribution, with respect to MQWs emission peak wavelength, in presence of agglomerates of V-pits surrounded by trench-like defects. The intensity of the redshifted wavelength contribution Manuscript

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“…[21][22][23][24] However, recent work has shown that Ld can reach up to a few tens of microns in high-efficiency structures grown by metal-organic chemical-vapor deposition on bulk GaN, as demonstrated by photoluminescence measurements. 25,26 In this study, we investigate the properties of implanted TJ µLEDs in detail and attribute the behaviour of size-dependent IQE to lateral carrier diffusion within the quantum well, thereby providing a detailed exploration of the underlying mechanisms.…”

Section: Introductionmentioning

confidence: 99%

Lateral carrier diffusion in ion-implanted ultra-small blue III-nitride microLEDs.

Slawinska,

Muziol,

Kafar

et al. 2024

Preprint

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Ultra-small micro-light emitting diodes (µLEDs), sized below 10 µm, are indispensable to create next-generation augmented and virtual reality (AR/VR) devices. Their high brightness and low power consumption could not only enhance the user experience by providing vivid and lifelike visuals but also extend device longevity. However, a notable challenge emerges: a decrease in efficiency with reduced size. This study casts light on this critical issue, investigating the lateral carrier diffusion in ion-implanted µLEDs. The implanted area restricts the carrier injection and defines the µLED size to diameters of 10, 5 and 2 µm without introduction of non-radiative recombination centres in the quantum well area. We observed a drop of efficiency for smaller devices, similarly as in the case of conventional µLEDs with etched sidewalls. Electroluminescence of µLEDs was studied using a Gaussian beam telescope to analyse light intensity profiles and hence the spatial carrier distribution within the active region of µLEDs. Lateral diffusion length was determined to be 11.2 µm at j=1 A/cm2 and decreased down to 2.4 µm for j=1000 A/cm2. We explain the underlying mechanism behind the size-dependent efficiency observed in µLEDs, attributing it to lateral carrier diffusion.

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Micro-photoluminescence to investigate lateral diffusion of charge carriers in InGaN/GaN MQWs

Cited by 3 publications

References 11 publications

Investigation of the Impact of Point Defects in InGaN/GaN Quantum Wells with High Dislocation Densities

Investigation of the Impact of Point Defects in InGaN/GaN Quantum Wells with High Dislocation Densities

V-Pits and Trench-Like Defects in High Periodicity MQWs GaN-Based Solar Cells: Extensive Electro-Optical Analysis

Lateral carrier diffusion in ion-implanted ultra-small blue III-nitride microLEDs.

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