a method for fabricating a plurality of individual light emitting diode units includes forming a gan epitaxial layer on a sapphire substrate , forming a plurality of exhaust trenches on the gan epitaxial layer , wherein the exhaust trenches define a plurality of individual light emitting diode units , forming a reflective layer on the gan epitaxial layer , attaching the reflective layer to a conductive substrate , removing the sapphire substrate from the gan epitaxial layer via a laser lift - off process , wherein a gas produced during the laser lift - off process is exhausted via the exhaust trenches , and dicing the conductive substrate along the exhaust trenches to form the plurality of individual light emitting diode units .