The search and investigation of resistive switching materials, the most consolidated form of solid-state memristors, has become one of the fastest growing areas in the field of electronics. This is not only due to the huge commercial interest in developing the so-called Resistive Random-Access Memories (ReRAMs) but also because resistive switching materials are gathering way to new forms of analog computation. Unlike in the field of traditional electronics technologies, where Silicon has monopolized most of the applications, the area of solid-state memristors is opened to a broad set of candidates that may contribute to unprecedented applications. In particular, the use of organic-based resistive switching materials can provide additional functionalities as structural flexibility for conformal integration or introduce new and cost-effective fabrication technologies. Following this new wave of organic memristive materials, this work aims at reviewing the existing models explaining the origins of resistive switching in Graphene Oxide, one of the most promising contenders on the battlefield of emerging memristive materials due to its low cost and easy processing methods. Within this manuscript, we will revisit the different theories supporting the phenomenology of resistive switching in this material nourishing the discussion with experimental results supporting the three main existing theories.

We present a graphene-based phase shifter for radio-frequency (RF) phase-array applications. The core of the designed phase-shifting system consists of a graphene field-effect transistor (GFET) used in a common source amplifier configuration. The phase of the RF signal is controlled by exploiting the quantum capacitance of graphene and its dependence on the terminal transistor biases. In particular, by independently tuning the applied gate-to-source and drain-to-source biases, we observe that the phase of the signal, in the super-high frequency band, can be varied nearly 200 • with a constant gain of 2.5 dB. Additionally, if only the gate bias is used as control signal, and the drain is biased linearly dependent on the former (i.e., in a completely analogue operation), a phase shift of 85 • can be achieved making use of just one transistor and keeping a gain of 0 dB with a maximum variation of 1.3 dB. The latter design can be improved by applying a balanced branch-line configuration showing to be competitive against other state-of-the-art phase shifters. This work paves the way towards the exploitation of graphene technology to become the core of active analogue phase shifters for high-frequency operation.

The Dirac voltage of a graphene field-effect transistor (GFET) stands for the gate bias that sets the charge neutrality condition in the channel, thus resulting in a minimum conductivity. Controlling its dependence on the terminal biases is crucial for the design and optimization of radio-frequency applications based on multiple GFETs. However, the previous analysis of such dependence carried out for single devices is uncomplete and if not properly understood could result in circuit designs with poor performance. The control of the Dirac point shift (DPS) is particularly important for the deployment of graphene-based differential circuit topologies where keeping a strict symmetry between the electrically balanced branches is essential for exploiting the advantages of such topologies. This note sheds light on the impact of terminal biases on the DPS in a real device and sets a rigorous methodology to control it so to eventually optimize and exploit the performance of radio-frequency applications based on GFETs.

Biological Field-Effect Transistors (BioFETs) have already demonstrated enormous potential for detecting minute amounts of ions and molecules. The use of two-dimensional (2D) materials has been shown to boost their performance...

We present a physics-based circuit-compatible model for pH-sensitive field-effect transistors based on twodimensional (2D) materials. The electrostatics along the electrolyte-gated 2D-semiconductor stack is treated by solving the Poisson equation including the Site-Binding model and the Gouy-Chapman-Stern approach, while the carrier transport is described by the drift-diffusion theory. The proposed model is provided in an analytical form and then implemented in Verilog-A, making it compatible with standard technology computer-aided design tools employed for circuit simulation. The model is benchmarked against two experimental transition-metal-dichalcogenide (MoS2 and ReS2) based ion sensors, showing excellent agreement when predicting the drain current, threshold voltage shift, and current/voltage sensitivity measurements for different pH concentrations.

Two-dimensional materials (2DMs) are a promising alternative to complement and upgrade high-frequency electronics. However, in order to boost their adoption, the availability of numerical tools and physically-based models able to...

Electronic devices based on bidimensional materials (2DMs) are the subject of an intense experimental research, that demands a tantamount theoretical activity. The latter must be hold up by a varied set of tools able to rationalize, explain and predict the operation principles of the devices. In the broad context of multi-scale computational nanoelectronics, there is currently a lack of simulation tools connecting atomistic descriptions with semi-classical mesoscopic device-level simulations and able to properly explain the performance of many state-of-the-art devices. To contribute to filling this gap we present a multi-scale approach that combines fine-level material calculations with a semi-classical drift-diffusion transport model. Its use is exemplified to assess 2DM-FET devices with strained channels, showing great potential to capture the changes in the crystal structure and their impact into the device performance. Interestingly, we verify the capability of strain in monolayer GaSe to enhance the conduction of one type of carrier, enabling the possibility to mimic the effect of chemical doping on 2D materials. These results illustrate the great potential of the proposed approach to connect levels of abstraction rarely connected before and thus contribute to the theoretical modeling of state-of-the-art 2DM-based devices.

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