This technology will be an improvement on the current method, for example, using phosphors to convert light of one color into another.
Gallium nitride (InGaN)LED is a kind of light emitting diode (LED) based on nitride of the third element. It was first manufactured in the 1990s more than 20 years ago, and has been developing continuously since then, becoming smaller and smaller, more and more powerful, efficient and durable. Today, InGaN LED can be found in countless industrial and consumer use cases, including signal and optical communication and data storage. It is very important in high-demand consumer applications, such as solid-state lighting, television, notebook computers, mobile devices, augmented (AR) and virtual reality (VR) solutions.
For more than 20 years, the growing demand for this kind of electronic equipment has promoted the research on semiconductors to achieve higher light output, reliability, longevity and versatility, which has LED to the demand for LEDs that can emit different colors of light. Traditionally, InGaN materials are used to generate purple and blue light in modern LEDs, while AlGaInP, a different type of semiconductor, is used to generate red, orange and yellow light. This is due to the poor performance of InGaN in red and amber spectra, which is due to the need for higher indium content, resulting in lower efficiency.
In addition, such InGaN LED with relatively high indium concentration are still difficult to manufacture with traditional semiconductor structures. Therefore, the realization of all-solid-state white light emitting devices is still an unattainable goal-all three primary colors are needed.
In order to meet these challenges, smart researchers wrote a paper entitled "Luminous V-Pit: an alternative method to realize luminescent indium-gallium-rich quantum dots". In their paper, the researchers describe a practical method to fabricate InGaN quantum dots with much higher indium concentration by using pre-existing defects in InGaN materials.
In this process, the so-called V-shaped pits formed by naturally occurring dislocations in the material directly form indium-rich quantum dots, that is, material islands that can emit light with longer wavelength. By growing these structures on traditional silicon substrates, the need for patterned or non-traditional substrates is further eliminated. The researchers also drew the composition of InGaN quantum dots with high spatial resolution, which provided visual confirmation of their morphology for the first time.
In addition to the formation of quantum dots, the nucleation of stacking faults (another inherent crystal defect) further promotes the emission of longer wavelengths.
Jing-Yang Chung, a clever graduate student and the main author of this paper, said: "For many years, researchers in this field have been trying to solve various challenges brought by inherent defects in InGaN quantum well structures. In a novel method, we turned to design a nano-pit defect to realize the direct growth platform of InGaN quantum dots. Therefore, our work proves the feasibility of using silicon substrate for the new indium-rich structure, which not only solves the challenge of low efficiency of long-wavelength InGaN optical transmitter at present, but also alleviates the problem of expensive substrate. "
In this way, the discovery of SMART represents an important step to overcome the inefficiency of InGaN in producing red, orange and yellow light. In turn, this work may be helpful to develop micro LED arrays composed of a single material in the future.
* * * Li and Sylvia, author and principal researcher, are in grade? Dr. ak added: "Our findings also have an impact on the environment. For example, this breakthrough may lead to the faster elimination of non-solid-state lighting sources, such as incandescent lamps, and even the current phosphate-coated blue InGaN LED, and the adoption of all-solid-state color mixing solutions, which will lead to a significant reduction in global energy consumption. "
Eugene Fitzgerald, CEO of SMART and principal researcher of LEES, said, "Our work may also have a broader impact on the semiconductor and electronics industries, because the new methods described here follow standard industrial manufacturing procedures and can be widely adopted and implemented on a large scale. On a more macro level, in addition to the energy-saving ecological benefits that InGaN may bring, our findings will also help the field to continue to study and develop new and efficient InGaN structures. "