title: Realizing controllable graphene nucleation by regulating the competition of hydrogen and oxygen during chemical vapor deposition heating.
abstract: Oxygen can passivate Cu surface active sites when graphene nucleates. Thus, the nucleation density is decreased. The CuO/Cu substrate was chosen for graphene domain synthesis in our study. The results indicate that the CuO/Cu substrate is beneficial for large-scale, single-crystal graphene domain synthesis. Graphene grown on the CuO/Cu substrate exhibits fewer nucleation sites than on Cu foils, suggesting that graphene follows an oxygen-dominating growth. Hydrogen treatment via a heating process could weaken the surface oxygen's role in limiting graphene nucleation under the competition of hydrogen and oxygen and could transfer the synthesis of graphene into a hydrogen-dominating growth. However, the competition only exists during the chemical vapor deposition heating process. For non-hydrogen heated samples, oxygen-dominating growth is experienced even though the samples are annealed in hydrogen for a long time after the heating process. With the temperature increases, the role of hydrogen gradually decreases. The balance of hydrogen and oxygen is adjusted by introducing hydrogen gas at a different heating temperatures. The oxygen concentration on the substrate surface is believed to determine the reactions mechanisms based on the secondary ion mass spectrometry test results. This study provides a new method for the controllable synthesis of graphene nucleation during a heating process.
authors: State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050, China. ghyu@mail.sim.ac.cn and CAS Center for Excellence in Superconducting Electronics, 865 Changning Road, Shanghai 200050, China and University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing 100049, China.
authors: Haoran
authors: H
authors: Zhang
authors: State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050, China. ghyu@mail.sim.ac.cn and CAS Center for Excellence in Superconducting Electronics, 865 Changning Road, Shanghai 200050, China and University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing 100049, China.
authors: Yaqian
authors: Y
authors: Zhang
authors: State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050, China. ghyu@mail.sim.ac.cn and CAS Center for Excellence in Superconducting Electronics, 865 Changning Road, Shanghai 200050, China.
authors: Yanhui
authors: Y
authors: Zhang
authors: State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050, China. ghyu@mail.sim.ac.cn and CAS Center for Excellence in Superconducting Electronics, 865 Changning Road, Shanghai 200050, China.
authors: Zhiying
authors: Z
authors: Chen
authors: State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050, China. ghyu@mail.sim.ac.cn and CAS Center for Excellence in Superconducting Electronics, 865 Changning Road, Shanghai 200050, China.
authors: Yanping
authors: Y
authors: Sui
authors: State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050, China. ghyu@mail.sim.ac.cn and CAS Center for Excellence in Superconducting Electronics, 865 Changning Road, Shanghai 200050, China and University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing 100049, China.
authors: Xiaoming
authors: X
authors: Ge
authors: State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050, China. ghyu@mail.sim.ac.cn and CAS Center for Excellence in Superconducting Electronics, 865 Changning Road, Shanghai 200050, China and University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing 100049, China.
authors: Rongxuan
authors: R
authors: Deng
authors: State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050, China. ghyu@mail.sim.ac.cn and CAS Center for Excellence in Superconducting Electronics, 865 Changning Road, Shanghai 200050, China.
authors: Guanghui
authors: G
authors: Yu
authors: Microwave Devices and Integrated Circuits Department, Institute of Microelectronics, Chinese Academy of Sciences, 3 West Beitucheng Road, Beijing 100029, China.
authors: Zhi
authors: Z
authors: Jin
authors: Microwave Devices and Integrated Circuits Department, Institute of Microelectronics, Chinese Academy of Sciences, 3 West Beitucheng Road, Beijing 100029, China.
authors: Xinyu
authors: X
authors: Liu