Wrinkle-dependent hydrogen etching of chemical vapor deposition-grown graphene domains Bin Wang a,b , Yanhui Zhang a , Haoran Zhang a , Zhiying Chen a , Xiaoming Xie a , Yanping Sui a , Xiaoliang Li a , Guanghui Yu a, * , Lizhong Hu b , Zhi Jin c , Xinyu Liu c a State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050, People’s Republic of China b School of Physics and Optoelectronic Technology, Dalian University of Technology, 2 Linggong Road, Dalian 116024, People’s Republic of China c Microwave Devices and Integrated Circuits Department, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100 029, People’s Republic of China ARTICLE INFO Article history: Received 1 September 2013 Accepted 24 December 2013 Available online 3 January 2014 ABSTRACT Hexagonal single-crystal graphene domains were grown on copper (Cu) foil via chemical vapor deposition and were etched with hydrogen at 950 °C from 7 to 60 min at atmospheric pressure. Numerous trenches were observed on the initial graphene domains after etching, and the trench patterns were closely associated with the Cu crystal orientation. No trenches were found if the etching process was conducted before cooling down. Thus, the etching trenches were bound up with the wrinkles formed during the cooling down pro- cess. Then, the process of etching on the wrinkles was examined. This simple hydrogen etching technology proved that wrinkles and point defects existed even in hexagonal sin- gle-crystal graphene domains. This method could be a convenient way to detect the distri- bution and morphology of wrinkles in graphene. Ó 2013 Elsevier Ltd. All rights reserved. 1. Introduction Given its interesting physical properties [1–3], graphene has drawn significant attention as a novel two-dimensional system with significant potential in future electronic and optoelectronic applications [4,5]. Compared with other graph- ene synthesis processes, graphene grown on copper (Cu) sub- strates via chemical vapor deposition (CVD) has the distinct advantage of providing extremely large-area graphene films transferable to other substrates for graphene electronics with compatible wafer-scale fabrication. However, carrier mobility in CVD graphene is less than that in exfoliated graphene [6–9]. Several studies have re- ported the effect of grain boundaries [10–13] in continuous CVD graphene on its electrical property. Improvements in growth techniques have led to large-scale grain sizes, which may enhance the electrical property of graphene. Meanwhile, the effect of wrinkles in continuous graphene films on elec- tronic transport was reported by Zhu et al. [14]. Sub-millimeter single-crystal graphene has been synthe- sized [15] and meets the size requirements of typical sub-micrometer graphene devices. For large-domain films, the effect of grain boundary on electrical property can be re- duced. Li et al. [16] reported that the electron mobility of the large-domain films extracted from field-effect transistor mea- surements was approximately 4000 cm 2 V À1 s À1 . However, this electron mobility is still less than that in exfoliated graphene. Thus, the electronic transport in the large graphene domain is also affected by other factors such as point defects and wrinkles. 0008-6223/$ - see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.carbon.2013.12.074 * Corresponding author. E-mail address: ghyu@mail.sim.ac.cn (G. Yu). CARBON 70 (2014) 75 – 80 Available at www.sciencedirect.com ScienceDirect journal homepage: www.elsevier.com/locate/carbon