InGaN laser diode with metal-free laser ridge using n(+)-GaN contact layers

We report on InGaN edge emitting laser diodes with a top metal electrode located beside the laser ridge. Current spreading over the ridge is achieved via a highly doped n(+)-type GaN layer deposited on top of the structure. The low sheet resistance of the n(+)-GaN layer ensures excellent lateral current spreading, while carrier injection is confined all along the ridge thanks to current tunneling at the interface between the n(+)-GaN top layer and the p(++)-GaN layer. Continuous-wave lasing at 400nm with an output power of 100mW is demonstrated on uncoated facet devices with a threshold current density of 2.4 kA.cm(-2). (C) 2016 The Japan Society of Applied Physics