Methods of performing fast thermal annealing in forming GaN light-emitting diodes (LEDs) are disclosed, as are GaN LEDs formed using fast thermal annealing having a time duration of 10 seconds or faster. An exemplary method includes forming a GaN multilayer structure having a n-GaN layer and a p-GaN layer that sandwich an active layer. The method includes performing fast thermal annealing of the p-GaN layer using either a laser or a flash lamp. The method further includes forming a transparent conducting layer atop the GaN multilayer structure, and adding a p-contact to the transparent conducting layer and a n-contact to the n-GaN layer. The resultant GaN LEDs have enhanced output power, lower turn-on voltage and reduced series resistance.