Improved Light-Output Power of GaN LEDs by Selective Region Activation

A novel selective high resistivity region (SHRR) is created under the p-pad metal electrode of a normal GaN light emitting diode. In conventional designs, light generated under the opaque p-pad metal electrode is absorbed or reflected by the contact and lost. In the SHRR design, the area under the p-pad metal electrode is selectively given a higher resistance, reducing current flow and light generation under the contact. Under constant current testing, the current normally passing through the SHRR region is instead distributed over the visible (i.e., useful) area of the device, resulting in significantly increased light-output power and luminous efficiency.