Technology and Applications of Micro-LEDs: Their Characteristics, Fabrication, Advancement, and Challenges

Abstract

Micro-light-emitting diodes (μLEDs) are getting much attention in display industry because of their outstanding optical and electrical characteristics. μLEDs have several advantages over liquid crystal displays (LCDs) and organic lightemitting diodes (OLEDs). μLEDs are showing long lifetimes, high reliability, high power efficiencies, high brightness, and fast response times with tiny pixels. However, for commercial usage, the high production cost and low external quantum efficiency (EQE) are the major hurdles. In this review, we briefly discuss the breakthroughs in μLED technology, fabrication methods, optical/ electrical characteristics, and challenges for display applications. In addition, the development of monolithic μLEDs and general device characteristics combined with various quantum dot patterning processes are systematically discussed. Potential solutions to address these challenges are also presented case by case.

In‐Plane Sensing Opportunities in MicroLED Displays

“…• AR, MR, and virtual reality (VR) (400-9,000 ppi) 6 ; • smartwatches, wearables, and smartphones (300-400 ppi) 7 ; and • tablets, laptops, TVs, and video walls (10-300 ppi). 8,9 The ultrahigh resolution needed for AR systems currently can Multiple paradigm shifts in a system's architecture could dramatically change the requirements of display management and general sensing.…”

A Critical Review on the Junction Temperature Measurement of Light Emitting Diodes

“…As the next generation micro-LEDs are gaining popularity [ 90 ], practices for performance characterization of micro-LEDs are also becoming a topic of interest. Although previous discussions suggest that heat accumulation in micro-LEDs is lower due to enhanced current spreading in active layers with size reduction [ 91 ], the studies of Feng et al [ 92 ] and Yu et al [ 93 ] emphasized the importance of T j for micro-LEDs by stating that the internal series resistance of micro-LEDs is expected to increase with their decreasing size.…”

Modified Distributed Bragg Reflectors for Color Stability in InGaN Red Micro-LEDs

“…To ease the mass-transfer process, the blue or UV LEDs with the color conversion structure such as phosphor or quantum dot (QD) layers are commonly used to achieve a full-color display. The advantages of QDs include a broad absorption spectrum, stable and narrow emission linewidths, and emission of pure and saturated colors which render them more suitable than phosphor for developing full-color micro-LED displays [ 9 , 10 ]. However, QD layers on the top of micro-LEDs still pose big problems for the resolution and uniformity of QD pattern, color conversion efficiency, reliability, and lifetime [ 11 , 12 , 13 ].…”