Controlling the density of pinhole defects in monolayer graphene synthesized via chemical vapor deposition on copper

Abstract

The chemical vapor deposition of monolayer graphene on metal foils and thin films typically yields graphene that appears to be continuous and complete but that actually contains a high density of pinhole defects. These pinhole defects can be present at densities greater than 1 µm-2 and are problematic for many applications, ranging from the implementation of graphene in electronics to its use as a diffusion barrier. Here, we characterize pinhole defects in graphene films that are grown on Cu foils and epitaxial Cu thin films using CH 4 as the precursor. On Cu foils, a relationship between surface roughness and the pinhole defect density is observed. A reduction in pinholes by a factor of ~40 is realized by decreasing the foil surface roughness via increasing the annealing temperature and duration. The pinhole density is further reduced by a factor of ~200 by using smoother epitaxial Cu thin films and additionally by extending the growth duration past the point of visual completion, as characterized by scanning electron microscopy. This study is expected to serve as a foundation for developing high quality substrates for graphene synthesis and realizing pinhole-free graphene.

Passivation of Germanium by Graphene for Stable Graphene/Germanium Heterostructure Devices

“…To quantify pinhole defects, we adapt a procedure previously described for graphene films grown on Cu substrates. , In this method, the samples are exposed to a solution that etches the substrate on which graphene is supported. The etchant selectively diffuses through pinholes because of their relatively large size, forming etch pits in the surface directly below pinholes.…”

State‐of‐the‐Art and Future Prospects for Atomically Thin Membranes from 2D Materials

“…Moreover, the transfer of 2D materials from their growth substrates onto a porous support for NATM fabrication tends to introduce additional large‐scale defects and tears . Some approaches for minimization of defects in 2D materials during scalable synthesis and transfer have indeed shown promise, but complete elimination of defects is extremely challenging . Hence, defect sealing and mitigation strategies will be required to obtain high performance in NATMs …”

Single-Ni Sites Embedded in Multilayer Nitrogen-Doped Graphene Derived from Amino-Functionalized MOF for Highly Selective CO2 Electroreduction

“…The dramatic decrease of the mesopore volume and surface area of Ni-NG-1100-acid could be attributed to the thermal sintering of carbon when the annealing temperature is higher than 1000 °C. 59 Further material characterization results reveal the following temperature effects on Ni-NG-X-acid samples. First, XRD patterns (Figure S23a) show that Ni-NG-X-acid samples exhibit better graphitization of carbon with higher annealing temperature where the intensity of the diffraction peak at 26°n otably rises.…”

“…Furthermore, with increasing annealing temperature from 700 to 1000 °C, the pore volume rises significantly at the mesopore pore-size range, indicating that more mesopores can be generated at a higher annealing temperature due to the aggregation of Ni NPs and the generation of hollow graphene shells. The dramatic decrease of the mesopore volume and surface area of Ni-NG-1100-acid could be attributed to the thermal sintering of carbon when the annealing temperature is higher than 1000 °C …”