Thin Ni film on graphene current spreading layer for GaN-based blue and ultra-violet light-emitting diodes

We introduced a thin nickel (Ni) film onto graphene as a current spreading layer for GaN-based blue and ultraviolet (UV) light emitting diodes (LEDs). The thin Ni film was confirmed to improve the electrical properties of the graphene by reducing the sheet and contact resistances. The advantages of Ni on graphene were more remarkable in UV LEDs, in which the operation voltage was reduced from 13.2V for graphene alone to 7.1 V. As a result, UV LEDs with Ni on graphene showed a uniform and reliable light emission, at similar to 83% of electroluminescence of indium tin oxide. (C) 2013 AIP Publishing LLC [http://dx.doi.org/10.1063/1.4802800]