Recently, Japanese and microwave sensor ufo led confirmed that the use of a V-shaped ridge structure to replace flat epitaxial wafers in LEDs can increase the light extraction efficiency by 20 times. The research team has produced the first evanescent wave (evanescent wave) by coupling. wave) to improve the light extraction efficiency of the LED semiconductor structure. Usually the evanescent wave is generated in the process of total internal reflection, and this wave decays quickly as soon as it leaves the reflection interface. Total internal reflection is the main reason that limits the luminous efficiency of optoelectronic devices. In order to increase the overall luminous efficacy of their products, LED manufacturers are constantly trying to improve extraction efficiency and eliminate total internal reflection. Recently, personnel from the Japan Institute of Industrial Technology (AIST) used evanescent waves to generate constructive coupling at the ridge structure, and extracted at least 50% of the luminous efficiency from the GaAs quantum well with the ridge structure. Figure: Evanescent wave coupling (Evanescent wave coupling) AIST researchers used MOCVD to fabricate the desired structure on a substrate with ridges etched on the surface, and measured the photoluminescence of the sample. The result was an extraction efficiency of about 50%. , Which is about 20 times of the traditional flat structure. With the support of the Paris Nano Institute, the team confirmed that evanescent waves play an important role through the analogy of physical processes. When the ridged back contains a platform with a width of 0.5 m, the light extraction rate reaches the maximum and decreases rapidly as the platform width increases.
