Yufeng Hao

Yufeng Hao was first-listed author of the 2013 study connecting surface oxygen on copper with growth of large single-crystal graphene domains. The team identified changes in nucleation density and growth behavior.^[ref]

This separates making nuclei from expanding existing domains. A treatment can change how many growth centers form as well as how quickly their boundaries advance. Faster growth alone does not guarantee a single crystal if many independently oriented domains are already present.

For an original planar-spacing estimate, suppose nuclei have number density $N$ per unit area and each ultimately occupies an area of order $1/N$. A characteristic spacing is thenAt $N=10^8{\mathrm{m}}^{-2}$, $\ell \sim 100\mu \mathrm{m}$. At $N=10^4{\mathrm{m}}^{-2}$, $\ell \sim 1\mathrm{cm}$. Reducing density by a factor of $10^4$ enlarges this characteristic length by a factor of 100, not $10^4$.

The estimate assumes a simple two-dimensional allocation of area; it does not describe nucleation timing, anisotropic growth or coalescence in detail. Those omissions matter in a real chemical vapor deposition experiment. The numerical densities are illustrative, not measurements quoted from Hao's paper. Material-growth control and spectroscopic characterization supply complementary evidence about the resulting graphene.