Direct electrode patterning on layered GaN on sapphire substrate by using needle-type dispenser system of Ag nanoinks

Ag electrodes were formed on InGaN/GaN multi-quantum well blue light emitting diode (LED) substrates by using needle-type dispensing of Ag nanoink and the heat treatment as wet processes. The patterns by using the needle-type dispenser system are drawn out of a dot matrix method like an inkjet printer, and thus, arbitrary graphics can be produced. After patterning, the conductive Ag films as electrodes were formed by sintering at 450°C for 30 minutes under the atmospheric conditions. The fabricated LED emitted blue light with a threshold and operating voltage of 3.3 and 4.4 V, respectively. These results suggest that the wet processed Ag electrodes have a potential for use in the production of GaN based LEDs.