Selective high resistivity region formation by a Ni catalyst on GaN light-emitting diodes

The activation of Mg-doped GaN using a thin Ni film has been investigated. The results show that the Ni film significantly enhances the hydrogen desorption from the GaN film, which could improve the hole concentration and the resistivity of a p-GaN film. By means of a selective high resistivity region (SHRR) with no Ni catalyst involved, the current blocking layer is thus simply developed beneath the p-pad electrode of the GaN-based light-emitting diodes (LEDs). The light-output intensity for the LED chip with a SHRR is significantly increased as compared with the conventional LED chip. This improvement can be explained by both the additional current injection into the effective active layer of the LED by the SHRR structure and the reduction in optical absorption under the p-pad electrode.