We grew graphene epitaxially on 6H-SiC(0001) substrate by the simulated annealing method. The mechanisms that govern the growth process were investigated by testing two empirical potentials, namely, the widely used Tersoff potential [J. Tersoff, Phys. Rev. B 39, 5566 (1989)] and its more refined version published years later by Erhart and Albe [Phys. Rev. B 71, 035211 (2005)]. Upon contrasting the results obtained by these two potentials, we found that the potential proposed by Erhart and Albe is generally more physical and realistic, since the annealing temperature at which the graphene structure just coming into view at approximately 1200 K is unambiguously predicted and close to the experimentally observed pit formation at 1298 K within which the graphene nucleates. We evaluated the reasonableness of our layers of graphene by calculating carbon-carbon (i) average bond-length, (ii) binding energy, and (iii) pair correlation function. Also, we compared with related experiments the various distance of separation parameters between the overlaid layers of graphene and substrate surface.
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机译:我们通过模拟退火方法在6H-SiC(0001)衬底上外延生长石墨烯。通过测试两个经验潜力,即广泛使用的Tersoff潜力,研究了控制生长过程的机制。物理化学Tersoff修订版B 39,5566(1989)]及其更完善的版本,几年后由Erhart和Albe [Phys。 B 71,035211(2005)。通过对比这两个电势获得的结果,我们发现Erhart和Albe提出的电势通常更物理和现实,因为明确预测了刚出现在大约1200 K的石墨烯结构的退火温度,并且接近实验观察到的在1298 K处形成的坑,石墨烯在其中成核。我们通过计算碳-碳(i)平均键长,(ii)结合能和(iii)对相关函数来评估我们的石墨烯层的合理性。此外,我们与相关实验比较了石墨烯覆盖层与基材表面之间分离参数的各种距离。
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