Congratulations to second year XM² postgraduate researcher Konstantinos-Andreas Anastasiou, whose article Laser-writable high-k dielectric for van der Waals nanoelectronics has been published in Science Advances.
State of the art van der Waals heterostructures rely on the use of hexagonal boron nitride as a gate dielectric, a tunnel barrier or a high-quality substrate material. The material is transferred mostly by chemical vapour deposition on top of the two-dimensional (2D) crystals, a technique which typically contains impurities that lead to leakage current in transistor devices. Other common deposition techniques used for SiO2 and HfO2 are not directly compatible with 2D materials and they tend to damage or modify the electronic properties of the underlying 2D crystal. In this paper, the authors 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 2D. Abstract below.
Abstract
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.
