Low-temperature growth of large-scale, single-crystalline graphene on Ir(111)

Guo Hui¹, Chen Hui¹, Que Yande¹, Zheng Qi¹, Zhang Yu-Yang^{1, 2}, Bao Li-Hong¹, Huang Li¹, Wang Ye-Liang¹, Du Shi-Xuan^{1, 2, †}, Gao Hong-Jun^{1, 2}

STM and Raman characterizations for the polycrystalline and single-crystalline graphene. (a) A large-scale STM image of polycrystalline graphene (U = −0.2 V and I = 0.1 nA). (b) A zoom-in STM image shows the moiré patterns and the domain boundary of R0 and R19 graphene (U = −0.05 V and I = 0.3 nA). (c) A large-scale STM image of the single-crystalline R0 graphene (U = −0.2 V and I = 0.1 nA). (d) A zoom-in STM image (U = −0.05 V and I = 0.3 nA). (e) Raman spectra for the polycrystalline (black dots) and single-crystalline (red dots) graphene.