▎ 摘　　要

NOVELTY - Preparing ultra-clean graphene involves adding the copper substrate in the tubular furnace, introducing carbon source gas and hydrogen for chemical vapor deposition, introducing carbon dioxide to process the other heating temperature area after depositing and processing to obtain ultra-clean graphene. USE - Method for preparing ultra-clean graphene used in optical and electric field (claimed). ADVANTAGE - The method enables to prepare ultra-clean graphene in simple manner, realizes large-scale production, and has high-quality and obtained large single crystal graphene film.