Enhanced Light Extraction Efficiency of GaN-Based LEDs With 3-D Colloidal-Photonic-Crystal Bottom Reflector

In this letter, self-assembled polystyrene nano-spheres with a diameter of 193 nm were used to fabricate the 3-D colloidal-photonic-crystal (CPC) bottom reflector for blue GaN-based light-emitting diodes (LEDs). Experimentally, the key point is the hydrophilic treatment of substrate and immediately to disperse the suspension into the substrate at 30 °C. The equilibrium between the particle transpo...