ZnO Nano-arrays on High Power Blue LED Chip for Enhanced Light Extraction Efficiency

ZnO nano-arrays were grown on high power GaN blue LED chip by low-cost chemical solution methods, which aimed to enhance the light extraction efficiency of LED chip. Various morphology was achieved by adjusting the concentration of ammonia and Zn2+ in the growth solution. With different growth solution, ZnO nano-arrays exhibited different morphologies and densities. The effect of nano-array morphology on the light extraction performance of the ZnO nano-array coated LED chip were studied. The mechanism of light extraction efficiency enhancement by nano-arrays was also discussed based on the experimental results. The result shows that ZnO nano-arrays with higher density and cone-shaped morphology are favorable for the improvement of light extraction in LED chip. ZnO nano-arrays grown at the optimum conditions can enhance the light extraction of LED chip by more than 60%. Meanwhile, ZnO nano-arrays have no significant effect on the electrical properties and electroluminescence stability of LED chip.