Open AccessDirect growth of graphene on GaN via plasma-enhanced chemical vapor deposition under N2 atmosphere
Author(s) -
Jan Mischke,
Joel Pennings,
Erik Weisenseel,
Philipp Kerger,
Michael Rohwerder,
W. Mertin,
G. Bacher
Publication year - 2020
Publication title -
2d materials
Language(s) - English
Resource type - Journals
ISSN - 2053-1583
DOI - 10.1088/2053-1583/ab8969
Subject(s) - graphene , chemical vapor deposition , materials science , light emitting diode , plasma enhanced chemical vapor deposition , sheet resistance , optoelectronics , electrode , plasma , nanotechnology , chemistry , layer (electronics) , physics , quantum mechanics
One of the bottlenecks in the implementation of graphene as a transparent electrode in modern opto-electronic devices is the need for complicated and damaging transfer processes of high-quality graphene sheets onto the desired target substrates. Here, we study the direct, plasma-enhanced chemical vapor deposition (PECVD) growth of graphene on GaN-based light-emitting diodes (LEDs). By replacing the commonly used hydrogen (H 2 ) process gas with nitrogen (N 2 ), we were able to suppress GaN surface decomposition while simultaneously enabling graphene deposition at <800 °C in a single-step growth process. Optimizing the methane (CH 4 ) flow and varying the growth time between 0.5 h and 8 h, the electro-optical properties of the graphene layers could be tuned to sheet resistances as low as ∼1 kΩ/□ with a maximum transparency loss of ∼12%. The resulting high-quality graphene electrodes show an enhanced current spreading effect and an increase of the emission area by a factor of ∼8 in operating LEDs.