title: Principle of direct van der Waals epitaxy of single-crystalline films on epitaxial graphene.
abstract: There are numerous studies on the growth of planar films on sp(2)-bonded two-dimensional (2D) layered materials. However, it has been challenging to grow single-crystalline films on 2D materials due to the extremely low surface energy. Recently, buffer-assisted growth of crystalline films on 2D layered materials has been introduced, but the crystalline quality is not comparable with the films grown on sp(3)-bonded three-dimensional materials. Here we demonstrate direct van der Waals epitaxy of high-quality single-crystalline GaN films on epitaxial graphene with low defectivity and surface roughness comparable with that grown on conventional SiC or sapphire substrates. The GaN film is released and transferred onto arbitrary substrates. The post-released graphene/SiC substrate is reused for multiple growth and transfer cycles of GaN films. We demonstrate fully functional blue light-emitting diodes (LEDs) by growing LED stacks on reused graphene/SiC substrates followed by transfer onto plastic tapes.
authors.affiliation: IBM T. J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, New York 10598, USA.
authors.forename: Jeehwan
authors.initials: J
authors.lastname: Kim
authors.affiliation: IBM T. J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, New York 10598, USA.
authors.forename: Can
authors.initials: C
authors.lastname: Bayram
authors.affiliation: IBM T. J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, New York 10598, USA.
authors.forename: Hongsik
authors.initials: H
authors.lastname: Park
authors.affiliation: IBM T. J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, New York 10598, USA.
authors.forename: Cheng-Wei
authors.initials: CW
authors.lastname: Cheng
authors.affiliation: IBM T. J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, New York 10598, USA.
authors.forename: Christos
authors.initials: C
authors.lastname: Dimitrakopoulos
authors.affiliation: IBM T. J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, New York 10598, USA.
authors.forename: John A
authors.initials: JA
authors.lastname: Ott
authors.affiliation: IBM T. J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, New York 10598, USA.
authors.forename: Kathleen B
authors.initials: KB
authors.lastname: Reuter
authors.affiliation: IBM T. J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, New York 10598, USA.
authors.forename: Stephen W
authors.initials: SW
authors.lastname: Bedell
authors.affiliation: IBM T. J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, New York 10598, USA.
authors.forename: Devendra K
authors.initials: DK
authors.lastname: Sadana