Carbon nanotube-graphene composite film as transparent conductive electrode for GaN-based light-emitting diodes

Abstract

Transparent conductive electrodes (TCE) made of carbon nanotube (CNT) and graphene composite for GaN-based light emitting diodes (LED) are presented. The TCE with 533-/sheet resistance and 88% transmittance were obtained when chemical-vapor-deposition (CVD) grown graphene was fused across CNT networks. With an additional 2-nm thin NiOx interlayer between the TCE and top p-GaN layer of the LED, the forward voltage was reduced to 5.12 V at 20-mA injection current. Moreover, four-fold improvement in terms of light output power was also observed. The improvement can be ascribed to the enhanced lateral current spreading across the hybrid CNTgraphene TCE before injection into the p-GaN layer THE MANUSCRIPT Carbon-based materials, for example one-dimensional carbon nanotube (CNT) and two-dimensional graphene, have been of great interest in broad range of applications, such as field-emission devices 1,2 , sensors 3,4 , lithium-sulfur batteries 5,6 , supercapacitors 7 and field-effect transistors 8. Both of the sp 2-hybridized carbon materials possess superior thermal conductivity, mechanical robustness and high electrical conductivities. The fact that they are only several atomic layer thin make them highly transparent. They are viable alternatives for transparent conductive electrode (TCE) in place of indium tin oxide (ITO) that is known to have chemical instability, scarcity in supply and brittleness _____________________________

Schottky Barrier Diode Characteristics of Graphene-GaN Heterojunction with Hexagonal Boron Nitride Interfacial Layer

“…Heterostructures of two dimensional layered materials and wide band gap semiconductors are of great importance for optoelectronic and nanoelectronic applications . Among the wide band gap semiconductors, gallium nitride (GaN) is one of the most attractive nitride semiconductor for applications in light‐emitting diodes (LEDs), solar cells, photodetectors, high‐electron‐mobility transistors, and high frequency power devices . Recently, significant interest has been given to fabricate graphene/GaN based Schottky junction considering the outstanding properties of both the materials.…”

Recognition of Spatial Distribution of CNT and Graphene in Hybrid Structure by Mapping with Coherent Anti-Stokes Raman Microscopy

“…In the recent years, the composites or hybrid materials based on graphene and carbon nanotube (CNT) have become a subject of extensive studies since synergistic effects of such kind of combination allowed for a significant progress in the development of novel flexible transparent electrodes [1][2][3], supercapacitors [4,5], and sensitive biological sensors [6]. It was demonstrated, for example, that in a polymer composite the presence of CNTs prevented aggregation of graphene nanoparticles and, on the other hand, graphene nanoparticles improved the dispersion of CNTs [7,8].…”

“…In Ref. [3,11], it was shown that the presence of a small number of CNTs on the surface of chemical-vapor-deposited (CVD) graphene results in a significant decrease of the sheet resistance, keeping the optical transmittance at the same level.…”

Preparation and Characterization of Reduced Graphene-P3HT Composite Thin Films for Use as Transparent Conducting Electrodes

“…The TCEs of multiwall carbon nanotubes (MWCNTs) incorporated with graphene quantum dots were made for GaN-based light emitting diodes (LED). A sheet resistance of 533 Ω and a transmittance of 88% were obtained when chemical-vapor-deposition grown graphene was fused across CNT networks [10]. Recently [11], we have prepared composite films of poly(3-hexylthiophene) and reduced graphene oxides (rGO-P3HT) for sensing ammonia gas.…”