Direct-writing of two-dimensional diodes by focused ion beams

摘要: In the past decade, electronic devices based on graphene and the related two-dimensional (2D) materials have exhibited outstanding figures of merit. However, so far, the fabrication of two-dimensional diodes, as elementary building blocks of electronic devices, still relies on manual or semi-automated handling processing. To unleash their commercial potential, the integration of 2D materials into a fully-automated fabrication line is a critical step. Here, we elucidate the focused ion-beam writing as an automated approach to construct lateral diodes on a 2D heterostructure (MoSe2/G) consisting of the stacked monolayer graphene and MoSe2. Se-defects generated by focused ion writing endow the 2D heterostructure with unique electronic properties like the adjustable work function and the quasi-metallic state, which allows for the construction of the barrier at the boundary of the writing and non-writing region. Benefiting from this feature, the ion-beam-written heterostructure is used to realize rectifying and current regulating diodes. Exhibiting comparable performance to traditional diodes, the rectifying diode has a rectification ratio of ~104, while the current regulative diode has a dynamic resistance larger than 4.5 MΩ. Furthermore, to illustrate practical applications of these diodes in digital logic electronics, AND and OR logic gates are directly inscribed on the heterostructure by ion beams. Our work demonstrates the focused ion-beam writing as an additional strategy for direct-writing of 2D diodes on graphene-based heterostructures.