By Josh Perry, Editor
Researchers from the University of Exeter (U.K.) created a new technique for creating van der Waals heterostructures with high-K dielectrics from two-dimensional materials, such as graphene, and with enhanced voltage scaling that would meet the needs of next-generation flexible electronics.
Graphene is one of the 2-D materials that can be used with this new fabrication technique for flexible nanoelectronics. (Wikimedia Commons)
The process, according to a report from the school, used an embedded laser in van der Waals heterostructure devices without damaging monolayers of 2-D materials. Working with HfS2, researchers oxidized the material through laser irradiation to enhance the interface between materials.
This is a breakthrough in production of next-generation electronics because previous attempts to build these structures were limited by the incompatibility of the high-K oxides and neighboring 2-D materials.
“This new technique allows for the creation of a host of fundamental nano-electronic and opto-electronic devices including dual gated graphene transistors, and vertical light emitting and detecting tunneling transistors,” the article added.
The research was recently published in Science Advances. The abstract stated:
“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.”