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.
The demand for augmented reality (AR), virtual reality (VR), wearables, and head‐up display (HUD) technology has fueled the rapid growth of next‐generation microdisplays. Despite their promise, challenges remain. This review analyzes performance metrics across various scenarios and provides valuable materials and technology perspectives for ongoing display technology. Our guidance for advanced microdisplay design aims to overcome obstacles and improve the field.
The phosphor‐converted light‐emitting diode (PC‐LED) has become an indispensable solid‐state lighting and display technologies in the modern society. Nevertheless, the use of scarce rare‐earth ...elements and the thermal quenching (TQ) behavior are still two most crucial issues yet to be solved. Here, this work successfully demonstrates a highly efficient and thermally stable green emissive MnI2(XanPO) crystals showing a notable photoluminescence quantum yield (PLQY) of 94% and a super TQ resistance from 4 to 623 K. This unprecedented superior thermal stability is attributed to the low electron–phonon coupling and the unique rigid crystal structure of MnI2(XanPO) over the whole temperature range based on the temperature‐dependent photoluminescence (PL) and single crystal X‐ray diffraction (SCXRD) analyses. Considering these appealing properties, green PC‐LEDs with a power efficacy of 102.5 lm W−1, an external quantum efficiency (EQE) of 22.7% and a peak luminance up to 7750 000 cd m−2 are fabricated by integrating MnI2(XanPO) with commercial blue LEDs. Moreover, the applicability of MnI2(XanPO) in both micro‐LEDs and organic light‐emitting diodes (OLEDs) is also demonstrated. In a nutshell, this study uncovers a candidate of highly luminescent and TQ resistant manganese halide suitable for a variety of emission applications.
A highly efficient and thermally stable manganese halide crystal, MnI2(XanPO) is demonstrated. The low electron–phono coupling along with rigid crystal structure contributes to excellent photoluminescent quantum yield of 94% with unprecedented near zero thermal quenching from 4 to 623 K. The crystals find their applications in light emitting diodes and micro light emitting diodes with excellent external quantum efficiency (EQE) up to 22.7% and power efficacy as high as 102.5 lm W−1.
The electrochemical nitrogen reduction reaction (NRR) is an attractive process for next‐generation ammonia synthesis; therefore, identifying a suitable catalyst for this reaction is critical. In ...recent years, transition‐metal dichalcogenides (TMDs) and their Janus structures have gained significant attention because of their outstanding catalytic properties. However, the synthesis of Janus TMDs remains challenging, and exposing their active sites is difficult when using a low‐dimensional structure to improve the catalytic activity. To date, relatively little research has been conducted in this area. Herein, emerging Janus WSeS/WSe2 heterostructure nanowalls are systematically explored. These nanowalls are used as a nitrogen fixation catalyst in electrolytes. The nanowalls demonstrate a significant NH3 yield rate and Faradaic efficiency of 13.97 µg h‐mgcat−1 and 35.24% at −0.3 V in 0.1 m HCl, as well as 15.96 µg h‐mgcat−1 and 40.2% in 0.1 M Na2SO4. This study presents an in‐depth analysis of the properties of Janus WSeS/WSe2 heterostructure nanowalls and a conceptual framework for linking TMD‐based catalysts and the NRR.
Herein, emerging Janus WSeS/WSe2 heterostructure nanowalls are systematically explored. These nanowalls are used as a nitrogen fixation catalyst in the electrolytes. The nanowalls exhibit a high NH3 yield rate and Faradaic efficiency of 13.97 µg h‐mgcat−1 and 35.24% at −0.3 V in 0.1 HCl, as well as 15.96 μg h‐mgcat‐1and 40.2% in 0.1 m Na2SO4. This study presents an in‐depth analysis of the properties of Janus WSeS/WSe2 heterostructure nanowalls and a conceptual framework for linking TMD‐based catalysts and the NRR.
Defect Inspection Techniques in SiC Chen, Po-Chih; Miao, Wen-Chien; Ahmed, Tanveer ...
Nanoscale research letters,
03/2022, Letnik:
17, Številka:
1
Journal Article
Recenzirano
Odprti dostop
With the increasing demand of silicon carbide (SiC) power devices that outperform the silicon-based devices, high cost and low yield of SiC manufacturing process are the most urgent issues yet to be ...solved. It has been shown that the performance of SiC devices is largely influenced by the presence of so-called killer defects, formed during the process of crystal growth. In parallel to the improvement of the growth techniques for reducing defect density, a post-growth inspection technique capable of identifying and locating defects has become a crucial necessity of the manufacturing process. In this review article, we provide an outlook on SiC defect inspection technologies and the impact of defects on SiC devices. This review also discusses the potential solutions to improve the existing inspection technologies and approaches to reduce the defect density, which are beneficial to mass production of high-quality SiC devices.
This study showcases a method for achieving high-performance yellow and red micro-LEDs through precise control of indium content within quantum wells. By employing a hybrid quantum well structure ...with our six core technologies, we can accomplish outstanding external quantum efficiency (EQE) and robust stripe bandwidth. The resulting 30 μm × 8 micro-LED arrays exhibit maximum EQE values of 11.56% and 5.47% for yellow and red variants, respectively. Notably, the yellow micro-LED arrays achieve data rates exceeding 1 Gbit/s for non-return-to-zero on-off keying (NRZ-OOK) format and 1.5 Gbit/s for orthogonal frequency-division multiplexing (OFDM) format. These findings underscore the significant potential of long-wavelength InGaN-based micro-LEDs, positioning them as highly promising candidates for both full-color microdisplays and visible light communication applications.
In this study, we have demonstrated the potential of InGaN-based red micro-LEDs with single quantum well (SQW) structure for visible light communication applications. Our findings indicate the SQW ...sample has a better crystal quality, with high-purity emission, a narrower full width at half maximum, and higher internal quantum efficiency, compared to InGaN red micro-LED with a double quantum wells (DQWs) structure. The InGaN red micro-LED with SQW structure exhibits a higher maximum external quantum efficiency of 5.95% and experiences less blueshift as the current density increases when compared to the DQWs device. Furthermore, the SQW device has a superior modulation bandwidth of 424 MHz with a data transmission rate of 800 Mbit/s at an injection current density of 2000 A/cm
2
. These results demonstrate that InGaN-based SQW red micro-LEDs hold great promise for realizing full-color micro-display and visible light communication applications.
Free-space optical communications hold promising advantages, including a large bandwidth, access to license-free spectrum, high data rates, quick and simple deployment, low power consumption, and ...relaxed quality requirements. Nevertheless, key technical challenges remain, such as a higher transmission efficiency, a lower transmission loss, and a smaller form factor of optical systems. Here, we demonstrate the viability of circular-polarization-multiplexed multi-channel optical communication using metasurfaces alongside a photonic-crystal surface-emitting laser (PCSEL) light source at wavelength of 940 nm. Through the light manipulation with metasurface, we split the linearly polarized incidence into left and right circular polarizations with desired diffraction angles. Such orthogonal polarization states provide a paradigm of polarization division multiplexing technique for light communication. The PCSEL light source maintains a low divergence angle of about 0.373 degrees after passing through an ultra-thin metasurface without further bulky collimator or light guide, making end-to-end (E2E) and device-to-device (D2D) communications available in a compact form. Both light source and modulated polarized light exhibit a − 3 dB bandwidth over 500 MHz, with successful 1 Gbit/s transmission demonstrated in eye diagrams. Our results affirm that metasurface effectively boosts transmission capacity without compromising the light source's inherent properties. Future metasurface designs could expand channel capacity, and its integration with PCSEL monolithically holds promise for reducing interface losses, thereby enhancing efficiency.
Light detection and ranging (LiDAR) sensor is widely recognized as a critical component for accurate perception. However, there are a host of challenges that impede their performance, including low ...spatial resolution, high costs, large size, low reliability, and susceptibility to interference. It is challenging to overcome these issues using a single LiDAR module, necessitating the need for a review of current LiDAR technologies. The paper commences by introducing the fundamental principles of various laser rangefinders and discussing the optical modulation technologies used to prevent interference and ghost images. Next, the paper delves into the latest developments in laser technology, with a focus on enhancing the switching rate, compliance with eye safety regulations, miniaturization, and improving stability. One highly promising innovation is the photonic crystal surface emitting laser (PCSEL), a novel light source that boasts high‐speed, small divergence angles, and high‐power output. Finally, the paper discusses the advancements made in non‐solid‐state scanning and solid‐state scanning, such as improving stability, increasing scanning angles, and optimizing the manufacturing of mechanical and micro‐electromechanical systems (MEMS). Additionally, the paper highlights the recent advancements in nanotechnology, specifically metasurface technology, which offers superior capabilities such as beam deflection, enhanced field‐of‐view (FOV), and dynamic modulation.
This paper tackles light detection and ranging challenges, delving into laser rangefinder principles, optical modulation, and advancements in laser tech. The promising photonic crystal surface emitting laser is a standout. Progress in scanning stability and angles is discussed as well, along with advancements in metasurface technology, enhancing beam deflection and field of view.
Nowadays, the flurry of autonomous vehicles is in full swing regarding light detection and ranging (LiDAR) and depth perception. For such visual perception, light plays an important role. We human ...beings recognize and distinguish surrounding details when the eye focuses light on the retina. For the LiDAR system, pulsed lasers are employed to measure the relevant range. Thus, appropriate light sources with high performance are in urgent demand. Auspiciously, a revolutionary semiconductor laser technology, namely the photonic-crystal surface-emitting laser (PCSEL), emerges over the past two decades. PCSEL exhibits not only a symmetric beam profile with narrow beam divergence but also a high-power operation with controllability. Therefore, it may be the holy grail for an ultracompact time-of-flight (ToF) LiDAR system. Hereupon, comprehensive analyses of PCSEL-relevant scientific publications and patent documents are conducted. We thereby review the development progress of PCSEL technology. Moreover, a systematic simulation is performed, providing real-time visualization of relevant point clouds with different beam divergence. PCSEL technology with unprecedented merits indeed turns a new leaf and a paradigm shift in LiDAR application is ongoing. It is believed that a lens-free and adjustment-free ultracompact apparatus in simplicity can be expected.
The monolithic integration of InGaN-based micro-LEDs is being of interest toward developing full-color micro-displays. However, the color stability in InGaN red micro-LED is an issue that needs to be ...addressed. In this study, the modified distributed Bragg reflectors (DBRs) were designed to reduce the transmission of undesired spectra. The calculated optical properties of the InGaN red micro-LEDs with conventional and modified DBRs have been analyzed, respectively. The CIE 1931 color space and the encoded 8-bit RGB values are exhibited for the quantitative assessment of color stability. The results suggest the modified DBRs can effectively reduce the color shift, paving the way for developing full-color InGaN-based micro-LED displays.
PDF
