Impact of growth rate on graphene lattice-defect formation within a single crystalline domain

Abstract

Chemical vapor deposition (CVD) is promising for the large scale production of graphene and other two-dimensional materials. Optimization of the CVD process for enhancing their quality is a focus of ongoing effort and significant progress has been made in decreasing the defectiveness associated with grain boundaries and nucleation spots. However, little is known about the quality and origin of structural defects in the outgrowing lattice which are present even in single-crystalline material and represent the limit of current optimization efforts. We here investigate the formation kinetics of such defects by controlling graphene’s growth rate over a wide range using nanoscale confinements. Statistical analysis of Raman spectroscopic results shows a clear trend between growth rate and defectiveness that is in quantitative agreement with a model where defects are healed preferentially at the growth front. Our results suggest that low growth rates are required to avoid the freezing of lattice defects and form high quality material. This conclusion is confirmed by a fourfold enhancement in graphene’s carrier mobility upon optimization of the growth rate.

Long‐Term Stability Control of CVD‐Grown Monolayer MoS2

“…The comparatively higher number of growth domains and the rather high growth coverage is suggested to cause these structures to coalescence in more defective manner with higher amount of grain boundaries. Cao et al mentioned a similar issue as a source of defect formation during growth in their theoretical studies . Furthermore, potentially due to higher number of seed formations and resulting higher growth rate, it is observed that the surface coverage of FD grown samples is higher than that of HO grown samples with multilayer to bulk growth zones (Figure S3(a) and (b), Supporting Information).…”

Application of Soxhlet Extractor for Ultra-clean Graphene Transfer

“…In contrast, the D-band was almost non-existent in the spectra of samples transferred using our Soxhlet method (see Supporting Information Figure S3). Defects in graphene originate either during the CVD growth 25 or transfer 1 processes, but it is noteworthy that both transfer processes were handled strictly identically prior to the PMMA-removal step, indicating that our novel transfer approach introduces fewer perturbations into the graphene film, leading to improved electronic and optical properties. Raman spectroscopy data are commonly used to evaluate the degree of doping and strain in graphene samples.…”

Progress and Prospects on the Fabrication of Graphene‐Based Nanostructures for Energy Storage, Energy Conversion and Biomedical Applications

“…[50] The quality of graphene product from CVD can be controlled with the use of different precursors. [51][52][53][54] For instance, Lee et al [55] produced mesoporous graphene nano-balls (MGBs) in large scale using a precursor assisted CVD with polystyrene balls and reduced iron as carbon source and catalyst respectively. A uniform number of graphene layers was achieved in this method as the carbon source was functionalised with sulfonic acid and carboxylic acid that facilitated homogeneous dispersion of template in catalyst solution.…”

“…The quality of graphene product from CVD can be controlled with the use of different precursors [51–54] . For instance, Lee et al [55] .…”