Light extraction efficiency enhancement in light-emitting diodes with indium tin oxide nano-craters

A simple and low cost method is described which improves extraction efficiency.The indium tin oxide (ITO) textured film was fabricated by using the self-assembly method and dry-etching.The surface morphologies and surface roughness were observed by using an atomic force microscope.The 1-V characteristics,output power and polar radiation pattern of the LEDs with and without textured ITO were measured for comparison.Cylinders and craters were formed on the ITO surface after the etching,the height of which increased with etching time.The output power of the devices is proportional to the etching time.Total internal reflection of light on the ITO-GaN interface is reduced due to the appearance of cylinders and craters,and their increasing height.Thus,the output power is improved.