Enhanced Light Extraction of GaN-Based Light-Emitting Diodes With a Hybrid Structure Incorporating Microhole Arrays and Textured Sidewalls

Abstract

GaN-based light-emitting diodes (LEDs) with a hybrid structure, including a microhole array and textured sidewalls (45° angle and convex patterns), are fabricated and studied. The use of this hybrid structure, formed using an inductively coupled plasma etching approach, causes reduced total internal reflection and increased scattering probability of photons at the GaN/air interface. Therefore, the opportunity for photons to find an escape cone and the related light extraction efficiency can be effectively increased. This designed hybrid structure provides substantial improvements in optical performance without any degradation in electrical properties. For instance, as compared with a conventional LED, the studied device with this hybrid structure (45° angle sidewalls) shows remarkable improvements of 20.9%, 24.3%, 20.5%, and 21.3% in light output power, luminous fluxes, external quantum efficiency, and wall-plug efficiency, respectively. In addition, higher intensities in the light emission mapping images and far-field patterns of the studied device are found. Therefore, the studied hybrid structure is promising for high-performance GaN-based LED applications.