Nonlithographic random masking and regrowth of GaN microhillocks to improve light-emitting diode efficiency

In this study, p-GaN microhillocks are grown on the top of a standard multiple-quantum-well (MQW) light-emitting diode (LED) with novel nonlithographic random masking. Such microhillocks can dramatically increase the external efficiency of the LED because of the destroyed symmetry of LED interfaces. By controlling metalorganic chemical vapor deposition (MOCVD) growth conditions, p-GaN microhillocks of various densities and sizes can be easily grown on a standard LED structure. The use of this novel method to grow microhillocks on the top of the LED can facilitate the control of the leakage current of LED compared that of the photo enhanced chemical (PEC) wet etch and inductively coupled plasma (ICP) dry etch methods.