Cu-Vapor-Assisted Growth of 2D SiO₂ Flakes and As-Oriented Graphene Arrays

The direct growth of two-dimensional (2D) materials on the surface of an insulating substrate holds significant promise for the construction of electronic and optoelectronic devices, facilitating their adaption to semiconductor manufacturing lines, but remains challenging. Herein, we present a facile and effective method for the direct synthesis of novel 2D SiO 2 domains and as-oriented graphene arrays with the assistance of Cu vapor by chemical vapor deposition. The morphology engineering of SiO 2 domains has been realized by modulating the growth temperature and time with high reproducibility and outstanding uniformity. Moreover, our method results in the formation of hexagonal graphene arrays featuring a highly aligned orientation on the as-grown SiO 2 flakes. These spontaneously formed vertical heterostructures provide an opportunity to directly construct devices without chemical etching transfer. As a result, the field-effect transistor based on the spontaneously formed graphene/2D SiO 2 heterostructure performed an ultrahigh charge mobility of 58650 cm 2 V –1 s –1 . The controllable synthesis of a 2D SiO 2 array and SiO 2 /graphene heterostructures opens up broad prospects for tailoring customized 2D materials, enabling a significant step toward realizing the full potential of 2D materials in electronic and optoelectronic device fabrication.