Effect of strain relaxation on performance of InGaN/GaN green LEDs grown on 4-inch sapphire substrate with sputtered AlN nucleation layer

Hu, Haiming; Zhou, Shengjun; Wan, Hui; Liu, Xingtong; Li, Ning; Xu, Haohao

doi:10.1038/s41598-019-40120-9

Cited by 46 publications

(23 citation statements)

References 40 publications

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“…Many cases of conventional heteroepitaxy are studied in the literature such as germanium on silicon [64,66], III-V materials on silicon [65,67,68], sapphire [69] or III-V [70], oxides on oxides and on silicon [71][72][73], ... However, since the topic of this work involves the epitaxy of vdW materials, more attention is given to the next two categories [74].…”

Section: Conventional Epitaxymentioning

confidence: 99%

Epitaxy of new layered materials: 2D chalcogenides and challenges of weak van der Waals interactions

Mortelmans,

De Gendt,

Heyns

et al. 2020

Preprint

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The application of new materials in nanotechnology opens new perspectives and enables groundbreaking innovations. Two-dimensional van der Waals materials and more specific, 2D chalcogenides are a promising class of new materials awaiting their usage in the semiconductor industry. However, the integration of van der Waals materials relying on industry-compatible manufacturing processes is still a major challenge. This is currently restricting the application of these new materials to the research laboratories environment only. The large-area and single-crystalline growth of van der Waals materials is one of the most important requirements to meet the challenging demands implied by the semiconductor industry. This review contributes to a more generalized understanding on the integration of van der Waals materials -and in more specific 2D chalcogenides -through the growth process of epitaxy. This, can pursue further the aspiration of large-area, single-crystalline and defect-free epitaxial integration of (quasi) van der Waals homo-and heterostructures into the great world of the semiconductor industry.

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Section: Conventional Epitaxymentioning

confidence: 99%

Epitaxy of new layered materials: 2D chalcogenides and challenges of weak van der Waals interactions

Mortelmans,

De Gendt,

Heyns

et al. 2020

Preprint

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“…The sapphire substrate was bonded onto the AlGaInP based red TFFC micro-LED to form the AlGaInP based red FC micro-LED [33]. The GaN based green/blue FC micro-LEDs structure comprised a metal layer, p-type GaN, a p-AlGaN electron blocking layer, InGaN/GaN multiple quantum wells, n-type GaN, and sapphire substrate [34][35][36][37][38]. Figure 2 shows the relationship between substrate thickness and the LEEs of each face of RGB micro-LEDs.…”

Section: Simulation Modelmentioning

confidence: 99%

Light Extraction Analysis of AlGaInP Based Red and GaN Based Blue/Green Flip-Chip Micro-LEDs Using the Monte Carlo Ray Tracing Method

et al. 2019

Self Cite

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Micro-scale light emitting diodes (micro-LEDs) commonly employ a thin-film flip-chip (TFFC) structure whose substrate is lifted off by an excimer laser. However, flip-chip (FC) micro-LEDs with a substrate can provide a sharp rise on sidewall emission by increasing the sidewall area. Here, we investigate the influence of substrate thickness, encapsulation, surface texture, microstructures between the substrate and epilayer, as well as the size, cutting shape, and angle of the chip on the light extraction efficiencies (LEEs) of FC micro-LEDs by using the Monte Carlo ray tracing method. We find that the LEE of the blue FC micro-LED chip increases by 46.5% over that of the blue TFFC micro-LED chip. After the encapsulation with the epoxy lens is applied, the LEEs of the blue TFFC micro-LED and blue FC micro-LED increase by 129% and 110.5%, respectively. The underlying mechanisms for the use of surface texture, patterned sapphire substrate, air-void array, and chip shaping technologies to improve the LEEs of FC micro-LEDs are also investigated in detail. We find that the LEEs AlGaInP based red FC micro-LED and GaN based blue/green FC micro-LEDs exhibit a sharp rise when the chip size drops from 30 to 10 µm. The inverted trapezoid FC micro-LED with patterned sapphire substrate (PSS) and encapsulation shows extraordinarily strong top emission and high collimation. We believe that our study offers a promising and practical route for obtaining high efficiency micro-LEDs.

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“…In article [ 3 ], a study was made of the influence of GaN/AlGaN layers on the characteristics of ultraviolet LEDs based on GaN, emitting at a wavelength of 375 nm. Publication [ 4 ] was devoted to the study of green LEDs InGaN/GaN and their implementation by growing several quantum wells to improve the quality of the crystal.…”

Section: Introductionmentioning

confidence: 99%

Intelligent LED Certification System in Mass Production

Malykhina

Tarkhov

Shkodyrev

et al. 2021

Sensors

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It is impossible to effectively use light-emitting diodes (LEDs) in medicine and telecommunication systems without knowing their main characteristics, the most important of them being efficiency. Reliable measurement of LED efficiency holds particular significance for mass production automation. The method for measuring LED efficiency consists in comparing two cooling curves of the LED crystal obtained after exposure to short current pulses of positive and negative polarities. The measurement results are adversely affected by noise in the electrical measuring circuit. The widely used instrumental noise suppression filters, as well as classical digital infinite impulse response (IIR), finite impulse response (FIR) filters, and adaptive filters fail to yield satisfactory results. Unlike adaptive filters, blind methods do not require a special reference signal, which makes them more promising for removing noise and reconstructing the waveform when measuring the efficiency of LEDs. The article suggests a method for sequential blind signal extraction based on a cascading neural network. Statistical analysis of signal and noise values has revealed that the signal and the noise have different forms of the probability density function (PDF). Therefore, it is preferable to use high-order statistical moments characterizing the shape of the PDF for signal extraction. Generalized statistical moments were used as an objective function for optimization of neural network parameters, namely, generalized skewness and generalized kurtosis. The order of the generalized moments was chosen according to the criterion of the maximum Mahalanobis distance. The proposed method has made it possible to implement a multi-temporal comparison of the crystal cooling curves for measuring LED efficiency.

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Effect of strain relaxation on performance of InGaN/GaN green LEDs grown on 4-inch sapphire substrate with sputtered AlN nucleation layer

Cited by 46 publications

References 40 publications

Epitaxy of new layered materials: 2D chalcogenides and challenges of weak van der Waals interactions

Epitaxy of new layered materials: 2D chalcogenides and challenges of weak van der Waals interactions

Light Extraction Analysis of AlGaInP Based Red and GaN Based Blue/Green Flip-Chip Micro-LEDs Using the Monte Carlo Ray Tracing Method

Intelligent LED Certification System in Mass Production

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