A Copper Iodide Semiconductor
A team of Korean researchers have developed a new LED material that can replace gallium nitride in producing blue light LEDs. This technological breakthrough was made while Korea has been stepping efforts to reduce its dependence on Japan in the material and parts sectors.
The Korea Institute of Science and Technology (KIST) announced on March 8 that a KIST team has succeeded in developing a new compound that can replace gallium nitride in producing blue light LEDs. The study was published in the latest online edition of the Scientific Report, a sister report publication of Nature.
The team produced blue light using a copper iodide (CuI) compound, which is made by synthesizing copper and iodine. "We have found that copper iodide semiconductors can emit blue light which is more than 10 times brighter than that of gallium nitride-based devices. They also excel in photoelectric efficiency and long-term device stability," the team said.
LEDs need red, green, and blue LEDs to produce white light. Japan has developed a method to make high-quality gallium nitride to produce blue light LEDs, which are used as a core device for smartphones, displays, electronic products and high-frequency devices.
The copper iodide semiconductor developed by the researchers can grow on low-cost silicon substrates with small defects, so it has the advantage of using the large-size silicon substrates (300 mm), which are currently commercially available. In addition, the copper iodide thin film’s growth temperature is similar to the temperature used in silicon-based processes (below 300 degrees Celsius), so that copper iodide thin films can be deposited without sacrificing performance. Therefore, it can be applied to a low-cost and simple silicon semiconductor process.
These research results are significant in that the study demonstrated new semiconductor material technology using a copper halogen compound for the first time in the world by growing high-quality copper halogen single crystal copper iodide on a silicon substrate and realizing high-efficiency blue light emission.