Fig. 2: Comparisons of graphene CVD growth behaviors on alumina fiber (AF) and quartz fiber (QF).
a SEM images of GAF obtained with the growth time of ~20 and ~70 min (top), and graphene-skinned quartz fiber (GQF) obtained with the growth time of ~60 and ~120 min (bottom). Scale bar, 1 μm. b, c Graphene nucleus densities (N) (b) and domain size (D) (c) obtained on AF and QF with various growth time. The linear fitting was in the form of N/D = k(t-t0) + b, where the slope k was the nucleation rate (b) or growth rate of domains (c), t (≥t0) and t0 were the growth and nucleation time, respectively, and b was the constant. d Coverage changing of graphene on AF and QF as a function of growth time. The nonlinear fitting was in the form of \(A=\sum {A}_{i} \sim a{(t-{t}_{0})}^{3}\), where A, Ai, a, \(t\), and \({t}_{0}\) represent the total coverage, area of each graphene domain, the coefficient of the nonlinear fitting, growth time and nucleation time. Growth conditions in a–d: 500 sccm Ar, 200 sccm H2, 20 sccm CH4, target temperature of ~1050 °C with changing growth time. e, Growth time consumed to realize the full coverage of graphene layers on AF and QF at various C/H ratios (growth conditions: 500 sccm Ar, 200 sccm H2, with various C/H ratios of 0.02, 0.04, 0.08, 0.10, 0.20, and 1.50 under the target temperature of ~1050 °C). f Raman spectra of GAF (top) and GQF (bottom) obtained at different growth temperatures of ~800, ~850, ~900, ~950, ~1000, and ~1050 °C (growth conditions: 500 sccm Ar, 200 sccm H2, 20 sccm CH4, with the growth time of ~200 min under above growth temperatures).
