Ellipsometry as a real-time optical tool for monitoring and understanding graphene growth on metals

Despite the recent advances in the chemical vapor deposition (CVD) of graphene, it is still a great challenge to control the thickness of graphene especially in real-time during the growth. So far, there are no reports on the real-time monitoring of graphene growth. Here, we show for the first time real-time in situ kinetic monitoring of graphene deposition by CVD on nickel. We demonstrate an optical nondestructive method of dynamic spectroscopic ellipsometry for controlling and optimizing the catalyst cleaning and annealing and, consequently, the graphene deposition and properties. The kinetic ellipsometry monitoring also highlights the mechanism of graphene formation. Discussion shows the applicability and industrial scalability of this ellipsometric method to the control of large-area graphene formation on any substrate. This approach opens a way to in-line real-time graphene metrology and is helpful in guiding the graphene growth process as we try to achieve reproducible and controllable research as well as industry processes for quality graphene formation.