Via-hole-based vertical GaN light emitting diodes

A vertical GaN-light emitting diode (LED) has been fabricated on a sapphire substrate with periodic via holes formed by a laser drilling technique. n-contact metal which was deposited on the backside of sapphire substrate was directly connected with an Ohmic metal of n-GaN layer through the via holes. The via-hole-based vertical GaN-LED demonstrated an optical power improvement of up to 12.5% with lower forward operating voltage compared with a conventional GaN-LED. In addition, this vertical LED showed just 0.8% and 1.5% variations of optical power and operation voltage at the 500h reliability test.