Recent Progress in Micro‐LED‐Based Display Technologies

Sajjad, Muhammad T.; Johar, Muhammad Ali; Hernández-Gutiérrez, C.A.; Usman, Muhammad; Łepkowski, S. P.

doi:10.1002/lpor.202100427

Cited by 131 publications

(87 citation statements)

References 191 publications

(270 reference statements)

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“…We extended our investigations to InN/In y Ga 1−y N DQWs. We assumed that these structures are pseudomorphically grown on metamorphic In y Ga 1−y N buffer layers or In y Ga 1−y N virtual substrates, which are used in optoelectronic devices [ 42 , 43 , 44 , 45 ]. In Figure 4 , we present the

for InN/In y Ga 1−y N DQWs with (a)

and

, (b)

and

, and (c)

and

.…”

Section: Resultsmentioning

confidence: 99%

Polarization-Induced Phase Transitions in Ultra-Thin InGaN-Based Double Quantum Wells

Łepkowski

Anwar

2022

Nanomaterials

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We investigate the phase transitions and the properties of the topological insulator in InGaN/GaN and InN/InGaN double quantum wells grown along the [0001] direction. We apply a realistic model based on the nonlinear theory of elasticity and piezoelectricity and the eight-band k·p method with relativistic and nonrelativistic linear-wave-vector terms. In this approach, the effective spin‒orbit interaction in InN is negative, which represents the worst-case scenario for obtaining the topological insulator in InGaN-based structures. Despite this rigorous assumption, we demonstrate that the topological insulator can occur in InGaN/GaN and InN/InGaN double quantum wells when the widths of individual quantum wells are two and three monolayers (MLs), and three and three MLs. In these structures, when the interwell barrier is sufficiently thin, we can observe the topological phase transition from the normal insulator to the topological insulator via the Weyl semimetal, and the nontopological phase transition from the topological insulator to the nonlocal topological semimetal. We find that in InGaN/GaN double quantum wells, the bulk energy gap in the topological insulator phase is much smaller for the structures with both quantum well widths of 3 MLs than in the case when the quantum well widths are two and three MLs, whereas in InN/InGaN double quantum wells, the opposite is true. In InN/InGaN structures with both quantum wells being three MLs and a two ML interwell barrier, the bulk energy gap for the topological insulator can reach about . We also show that the topological insulator phase rapidly deteriorates with increasing width of the interwell barrier due to a decrease in the bulk energy gap and reduction in the window of In content between the normal insulator and the nonlocal topological semimetal. For InN/InGaN double quantum wells with the width of the interwell barrier above five or six MLs, the topological insulator phase does not appear. In these structures, we find two novel phase transitions, namely the nontopological phase transition from the normal insulator to the nonlocal normal semimetal and the topological phase transition from the nonlocal normal semimetal to the nonlocal topological semimetal via the buried Weyl semimetal. These results can guide future investigations towards achieving a topological insulator in InGaN-based nanostructures.

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for InN/In y Ga 1−y N DQWs with (a)

and

, (b)

and

, and (c)

and

.…”

Section: Resultsmentioning

confidence: 99%

Polarization-Induced Phase Transitions in Ultra-Thin InGaN-Based Double Quantum Wells

Łepkowski

Anwar

2022

Nanomaterials

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“…Next, we turn on red, green, and blue mini-LEDs in the RGB mini-LED array at the same time, and then analyze the impact among three mini-LEDs. In order to evaluate the degree of color crosstalk among them, we define an evaluation metric as chromatic aberration (∆E), and it is expressed by (5) where u and v refer to the chromaticity coordinates in the CIE 1976 color space when three mini-LEDs are turned on at the same time, and u0 and v0 are the chromaticity coordinates when they are lit individually. Figure 5(a) shows the variation of ∆E with J for three colored mini-LEDs.…”

Section: Luminance Analyses and Simulation Of Rgb Mini-led Arraymentioning

confidence: 99%

“…The power consumption of micro-LED display is only 10% of LCD and 50% of OLED [2], [3]. Therefore, the micro-LED displays own extensive application prospects in the field of portable and wearable devices, visible light communication (VLC), and augment reality/virtual reality (AR/VR) devices [4], [5], possessing extensive practical significance and commercial value.…”

Section: Introductionmentioning

confidence: 99%

Explore Luminance Attenuation and Optical Crosstalk of RGB Mini Light-Emitting Diode via Microscopic Hyperspectral Imaging

Zheng

Guo

et al. 2022

IEEE J. Electron Devices Soc.

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In this article, we experimentally and quantitatively investigate the luminance attenuation for red, green, and blue mini light-emitting diodes (LEDs), and the optical crosstalk in the RGB mini-LED array under different working currents via the microscopic hyperspectral imaging technique. The evaluation metrics of luminance attenuation for one single mini-LED subpixel and luminance influence among all three colored mini-LEDs are well defined to quantitatively describe the optical crosstalk among three mini-LED subpixels in the array. We also compare the size-dependent behaviors of luminance attenuation for blue and green mini-LEDs with an emission peak of about 465 nm and 529 nm, respectively. The minimum pixel pitch of blue and green mini-LEDs with different chip sizes is obtained through optical simulation based on LightTools software, so that the optical crosstalk can be reduced. Finally, we believe that this study could provide a useful guidance for selecting suitable working current conditions while driving the mini-LED display with suitable pixel size and pixel pitch to reduce both the optical and color crosstalk in the mini-LED display.

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“…GaN has a wide application and is not only limited to power electronics. Due to GaNs ability to conduct electrons more efficiently than silicon, GaN is also used in radio, light-emitting diode [24][25][26], in HEMTs [27], laser photodiode detectors [28], and radiation detectors [29].…”

Section: Problem With Using Gan As a Secondary Rectifiermentioning

confidence: 99%

High Step-Up Flyback with Low-Overshoot Voltage Stress on Secondary GaN Rectifier

et al. 2022

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This paper presents a new technique to mitigate the high voltage stress on the secondary gallium nitride (GaN) transistor in a high step-up flyback application. GaN devices provide a means of achieving high efficiency at hundreds (and thousands) of kHz of switching frequency. Presently however, commercially available GaN is limited to only a 650 V absolute voltage rating. Such a limitation is challenging in high step-up flyback applications due to the secondary leakage. The leakage imposes high voltage stress on the secondary GaN rectifier during its turn-off transient. Such stress may cause irreversible damage to the GaN device. A new method of leakage bypass is presented to mitigate the high voltage stress issue. The experimental results suggest that when compared to conventional secondary active clamp, a 2.3-fold reduction in overshoot voltage stress percentage is achievable with the technique. As a result, it is possible to utilize GaN as the rectifier while keeping the peak voltage stress within the 650 V limitation with the technique.

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Recent Progress in Micro‐LED‐Based Display Technologies

Cited by 131 publications

References 191 publications

Polarization-Induced Phase Transitions in Ultra-Thin InGaN-Based Double Quantum Wells

Polarization-Induced Phase Transitions in Ultra-Thin InGaN-Based Double Quantum Wells

Explore Luminance Attenuation and Optical Crosstalk of RGB Mini Light-Emitting Diode via Microscopic Hyperspectral Imaging

High Step-Up Flyback with Low-Overshoot Voltage Stress on Secondary GaN Rectifier

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