Laser-writable high-k dielectric for van der Waals nanoelectronics.

Similar to silicon-based semiconductor devices, van der Waals heterostructures require integration with high- k oxides. Here, we demonstrate a method to embed and pattern a multifunctional few-nanometer-thick high- k oxide within various van der Waals devices without degrading the properties of the neighboring two-dimensional materials. This transformation allows for the creation of several fundamental nanoelectronic and optoelectronic devices, including flexible Schottky barrier field-effect transistors, dual-gated graphene transistors, and vertical light-emitting/detecting tunneling transistors. Furthermore, upon dielectric breakdown, electrically conductive filaments are formed. This filamentation process can be used to electrically contact encapsulated conductive materials. Careful control of the filamentation process also allows for reversible switching memories. This nondestructive embedding of a high- k oxide within complex van der Waals heterostructures could play an important role in future flexible multifunctional van der Waals devices.