Tuning the infrared resonance of thermal emission from metasurfaces working in near-infrared.

We simulated numerically and demonstrated experimentally that the thermal emittance of a metasurface consisting of an array of rectangular metallic meta-atoms patterned on a layered periodic dielectric structure grown on top of a metallic layer can be tuned by changing several parameters. The resonance frequency, designed to be in the near-infrared spectral region, can be tuned by modifying the number of dielectric periods, and the polarization and incidence angle of the incoming radiation. In addition, the absorbance/emittance value at the resonant wavelength can be tuned by modifying the orientation of meta-atoms with respect to the illumination direction.

3D Graphene Foam by Chemical Vapor Deposition: Synthesis, Properties, and Energy-Related Applications.

In this review, we highlight recent advancements in 3D graphene foam synthesis by template-assisted chemical vapor deposition, as well as their potential energy storage and conversion applications. This method offers good control of the number of graphene layers and porosity, as well as continuous connection of the graphene sheets. The review covers all the substrate types, catalysts, and precursors used to synthesize 3D graphene by the CVD method, as well as their most viable energy-related applications.

Tunable Microwave Filters Using HfO-Based Ferroelectrics.

In this paper, we present microwave filters that are based on 6-nm-thick ferroelectric thin films of hafnium oxide doped with zirconium (HfZrO), which are tunable continuously in targeted bands of interest within the frequency range 0.1-16 GHz, when the applied direct current (DC) voltage is swept between 0 V and 4 V. Here, we exploit the orthorhombic polar phase in HfO through a careful doping using zirconium in an Atomic Layer Deposition (ALD) process, in order to guarantee phase stabilization at room temperature.

Memtransistors Based on Nanopatterned Graphene Ferroelectric Field-Effect Transistors.

The ultimate memristor, which acts as resistive memory and an artificial neural synapse, is made from a single atomic layer. In this manuscript, we present experimental evidence of the memristive properties of a nanopatterned ferroelectric graphene field-effect transistor (FET). The graphene FET has, as a channel, a graphene monolayer transferred onto an HfO-based ferroelectric material, the channel being nanopatterned with an array of holes with a diameter of 20 nm.

Graphene bandgap induced by ferroelectric HfO doped with Zr (HfZrO).

Motivated by the need to open a bandgap in graphene, we show experimentally that the CMOS-compatible ferroelectric HfZrO substrate induces a bandgap of 0.18 eV in graphene monolayer, which allows top-gate graphene/HfZrO/SiO/Si field-effect transistors to have high on/off current ratio, of about 10, at small drain voltages, of 0.5 V, and for gate voltage spans of only 3.