title: Vertical pillar-superlattice array and graphene hybrid light emitting diodes.
abstract: We report a type of device that combines vertical arrays of one-dimensional (1D) pillar-superlattice (PSL) structures with 2D graphene sheets to yield a class of light emitting diode (LED) with interesting mechanical, optical, and electrical characteristics. In this application, graphene sheets coated with very thin metal layers exhibit good mechanical and electrical properties and an ability to mount, in a freely suspended configuration, on the PSL arrays as a top window electrode. Optical characterization demonstrates that graphene exhibits excellent optical transparency even after deposition of the thin metal films. Thermal annealing of the graphene/metal (Gr/M) contact to the GaAs decreases the contact resistance, to provide enhanced carrier injection. The resulting PSL-Gr/M LEDs exhibit bright light emission over large areas. The result suggests the utility of graphene-based materials as electrodes in devices with unusual, nonplanar 3D architectures.
authors.affiliation: Division of Materials Science and Engineering, Hanyang University, Seoul 133-791, Korea.
authors.forename: Jung Min
authors.initials: JM
authors.lastname: Lee
authors.forename: Jae Woong
authors.initials: JW
authors.lastname: Choung
authors.forename: Jaeseok
authors.initials: J
authors.lastname: Yi
authors.forename: Dong Hyun
authors.initials: DH
authors.lastname: Lee
authors.forename: Monica
authors.initials: M
authors.lastname: Samal
authors.forename: Dong Kee
authors.initials: DK
authors.lastname: Yi
authors.forename: Chul-Ho
authors.initials: CH
authors.lastname: Lee
authors.forename: Gyu-Chul
authors.initials: GC
authors.lastname: Yi
authors.forename: Ungyu
authors.initials: U
authors.lastname: Paik
authors.forename: John A
authors.initials: JA
authors.lastname: Rogers
authors.forename: Won Il
authors.initials: WI
authors.lastname: Park