Micro‐Light‐Emitting Diodes Based on InGaN Materials with Quantum Dots

Abstract

gallium arsenide, GaAs; indium antimonide, InSb) generation semiconductor materials, third-generation semiconductor materials, such as GaN semiconductors, have improved physical and chemical characteristics, such as a wider band gap, higher frequency, higher efficiency, higher breakdown voltage, higher thermal conductivity, higher thermal resistance, and higher radiation resistance. [1,2] Therefore, they are better suited for electronic or optoelectronic devices that operate in harsh environments due to their superior energy efficiency.In particular, GaN and related alloys, also known as III-nitrides, are essential materials in many modern optoelectronic applications due to the superior benefits provided by these materials and are commercially successful in the sectors of solid lighting and laser technologies. [3,4] III-nitrides can crystallize in either wurtzite (WZ) or zinc-blende (ZB) phases, with the hexagonal WZ phase being more thermodynamically stable. [5] The band gap remains direct across the entire composition range from aluminum nitride (6.4 eV, ≈3.5 eV for GaN) to indium nitride (≈0.65 eV), with the band gap energy ranging from the deep-ultraviolet to the near infrared spectrum. [3,4,6] Because of these properties, III-nitrides are particularly useful for optoelectronic devices such as LEDs, laser diodes (LDs), and photodetectors, where a direct band gap is essential for efficient device operation. [7,8] The rapid growth of III-nitride technology in optoelectronics has been accelerated by the introduction of blue LEDs with indium gallium nitride (InGaN) as the active layer, which has become important devices in various applications since the photoluminescence from high-quality InGaN films was shown in 1992 and the first blue LEDs were demonstrated in 1993. [9,10] Due to their high efficiency, chemical inertness, and long operating lifetime, InGaN-based LEDs have been widely used in our daily life, such as in traffic signals, full-color displays, back-light sources for liquid-crystal displays, and mobile electronic devices, as well as in general lighting, including automobile lamps, architecture illumination, and household lighting. [11][12][13][14] These LEDs are not only a new type of light source but also a prospective contributor to global energy savings. [11] In recent years, the need for high pixel density, high power efficiency, high luminance, and high refresh rate next generation displays (i.e., wearable/flexible, automotive head-up, and augmented/virtual reality (AR/VR) displays) has piqued the Micro-light-emitting diodes (Micro-LEDs) based on gallium nitride (GaN) materials offer versatile platforms for various applications, including displays, data communication tools, photodetectors, and sensors. In particular, the introduction of Micro-LEDs in the optoelectronic industry enables the development of novel short-distance wireless communication applications for the Internet of Things as well as near-to-eye displays for virtual reality and augmented reality. Micro-LEDs used in conjunction with...

Integration of ternary I-III-VI quantum dots in light-emitting diodes

“…Photoluminescence lifetime in semiconductors refers to the time that the electron remains in the conduction band before it returns to the valence band. Several organic compounds exhibit lifetimes of 10 nanoseconds, and carbon dots have lifetimes ≤20 ns, while TQDs display values of at least 100 ns ( Hutton et al, 2017 ; Liu et al, 2020 ). The CuInS 2 photoluminescence lifetime is in the range from 100 to 300 ns, and AgInS 2 shows a photoluminescence lifetime in the range from 110 to 450 ns.…”

“…Generally, a WLED is formed by a mixture of different color materials in the mid-layer, particularly blue, green, and red, where the color blue is an LED chip from InGaN, the color green is an LED chip from a phosphor compound, and the color red is an LED chip from TQDs (such as the materials with primary colors red, yellow, and blue). TQDs are used as additives in the mid-layer in a prefabricated LED chip (InGaN) ( Liu et al, 2022 ).…”

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

“…The ultra-small LEDs are used in assembling RGB micro-LEDs to achieve full-color displays and allow the brightness of each pixel to be controlled in a dynamic range. In general, RGB micro-LED pixels can be obtained from the mass transfer, InGaN/AlGaN core-shell nanowire heterostructure [ 14 ], multi-quantum wells (MQW), or different InGaN-based substrates and monolithically integrated for achieving full-color displays [ 15 ]. Among them, InGaN-based blue and green micro-LEDs have attracted a lot of attention due to the efficiency and modulation bandwidth.…”

8.2: Invited Paper: The Full‐color Micro‐LED Display with Quantum Dots Inkjet Printing

“…These frontier technologies based on micro-LED have attracted huge attention in research and industry fields. However, to achieve commercial applications, it has a long way to solve many challenges, including epitaxy wafer, driver circuit, mass transfer and full-color technology [4,5]. The full-color technology for micro-LED is the one of the significant challenges in display field.…”