A new approach to the fabrication of VO2 nanoswitches with ultra-low energy consumption.

A new approach for the formation of free-standing vertical resistive nanoswitches based on VO2 nanocrystals (NCs) with embedded conductive nanosharp Si tips is demonstrated in the present article. This approach consists in the chemical vapor deposition synthesis of VO2 NCs on the apices of sharp conductive nanotips formed on a Si substrate by the standard methods of planar silicon technology. The amplification of the electric field and current density at the tip apex inside a high-quality VO2 NC leads to a record-breaking reduction of switching voltage (by a factor of 20-70) in comparison with conventional geometry devices with planar contacts. Our pulse measurements showed that the extremely low energy equal to 4.2 fJ was consumed for the switching in such NCs, and the total number of switching cycles in one NC without degradation exceeded 1011. The proposed approach can be extended to the formation of large arrays of such nanoswitches. We showed that periodic arrays of individual VO2 NCs were selectively synthesized on sharp Si tips. The nanosizes of the switches, ultra-low power consumption for switching and the possibility of forming dense arrays of such objects make the fabricated nanoswitches promising devices for future neuromorphic systems.

Films fabricated from partially fluorinated graphene suspension: structural, electronic properties and negative differential resistance.

The band structure and electric properties of films created from a partially fluorinated graphene suspension are analyzed in this paper. As may be inferred from the structural study, graphene islands (quantum dots) are formed in these films. Various types of negative differential resistance (NDR) and a step-like increase in the current are found for films created from the fluorinated graphene suspension. NDR resulting from the formation of the potential barrier system in the film and corresponding to the theoretical prediction is observed for a relatively low fluorination degree. The origin of the NDR varies with an increase in the fluorination degree of the suspension. The observation of NDR in the fluorinated films widens the range of application of such films, including as active device layers fabricated using 2D printed technologies on rigid and flexible substrates.