Optimization of dispersion angle in resonant cavity micro-light-emitting diode using multilayer DBR and microlens structures

In this paper, the fabrication and the corresponding performance characteristics of resonant cavity micro-light-emitting diodes (RC-μ-LEDs) are examined, with particular emphasis placed on reducing the light emission angle to enhance their application efficiency. A stepped quantum well structure and a multilayer aperture distributed Bragg reflector (DBR) are used to reduce the light emission angle, and two different approaches are investigated: one is by adding a multilayer DBR structure, and the other is by incorporating a microlens (ML) structure. The experimental results show that both adjusting the DBR cycles and adding microlenses can effectively reduce the dispersion angle of light emission, and thus improving the directionality of light, wavelength stability, and the overall device performance. Such highly directional light sources offer great solutions for optical communications, micro-LEDs, and augmented reality (AR) applications.