▎ 摘　　要

Multiple methods with distinctive strengths and drawbacks have been devised so far to produce graphene. However, they all need post-synthesis transfer steps to characterize the product. Here we report the synthesis of pristine graphene inside the transmission electron microscope using gold as catalyst and self-removing substrate without employing a specialized specimen holder. The process occurs at room temperature and takes place within milliseconds. The method offers the possibility of precise spatial control for graphene production and immediate characterization. Briefly, the irradiating electrons generate secondary electrons leading to surface charging if the gold particles reside on a poorly conducting support. At a critical charge density, the particle ejects ions mixed with secondary electrons (plasma) causing the particle to shrink. Simultaneously, hydrocarbon contamination within the electron microscope is cracked, thus providing carbon for the growth of graphene on the particle's surface. The Technique is potentially attractive for the manufacture of in situ graphene-based devices.