0000000001172377
AUTHOR
R. Danneau
Radiofrequency performances of different Graphene Field Effect Transistors geometries
In this work, we investigated on microwave parameters geometry dependence in Graphene Field Effect Transistors (GFETs). A DC and RF characterization of the fabricated GFETs has been performed. The parametric analysis was carried out on 24 GFET families fabricated on the same chip and differing only for the channel length (Δ) and the gate length (Lg). In order to obtain a statistical average, each family included ten devices with the same geometry.Our study demonstrates that the output resistance and the cut-off frequency depend on both Δ and Lg. As expected, Rout increases with the graphene channel surface thus confirming the good quality of the fabrication procedures. An optimum region whi…
Phase-dependent microwave response of a graphene Josephson junction
Gate-tunable Josephson junctions embedded in a microwave environment provide a promising platform to in situ engineer and optimize novel superconducting quantum circuits. The key quantity for the circuit design is the phase-dependent complex admittance of the junction, which can be probed by sensing a radio frequency SQUID with a tank circuit. Here, we investigate a graphene-based Josephson junction as a prototype gate-tunable element enclosed in a SQUID loop that is inductively coupled to a superconducting resonator operating at 3 GHz. With a concise circuit model that describes the dispersive and dissipative response of the coupled system, we extract the phase-dependent junction admittanc…
Fabrication and analysis of the layout impact in Graphene Field Effect Transistors (GFETs)
In this work we focused on the analysis of Graphene Field Effect Transistor (GFET) microwave parameters dependence on geometries. In particular, a statistical, experimental investigation of the cut-off frequency (ft) dependency on both the gate-drain/source distance (Δ) and the gate length (Lg) was carried out. 24 GFET families on the same chip were fabricated, each one made of 10 identical (same geometry) devices. The analysis of the measured data shows that ft is both Δ and Lg dependent, and that there exists an optimal region in Δ and Lg design space.
Impact of GFETs geometries on RF performances
Graphene is a relatively new material whose unique properties have attracted significant interest for its use in electronic and photonic applications. In particular, field effect has been proved in graphene samples and the observed high carrier mobility makes graphene an interesting solution for high frequency electronics. In this work, we focused on the analysis of microwave parameters dependence on geometries in Graphene Field Effect Transistors (GFETs). In particular, a statistical, experimental investigation of the cut-off frequency (fT) and of the output impedance (Zout) dependency on both the gate-drain/source distance (Δ) and the gate length (Lg) was carried out. 24 GFET families wer…
Photoelectrical response of Graphene Field Effect Transistors (GFETs)
In this work, we present Graphene Field Effect Transistors (GFETs) with photoelectrical response due to the photovoltaiceffect. Our final aim is to use a GFET to down convert an optical to a radiofrequency signal. The technological steps used for the devices fabrication as well as the photoelectrical characterization will be reported. Photoelectrical measurements were performed by using a 405 nm laser diode source, whose output beam was pulse amplitude-modulated at 1.33 kHz by means of a laser driver. The electrical signal out of the GFETs (in a common source amplifier configuration) was measured using a lock-in amplifier synchronized to the same reference frequency of the laser driver. Thi…
Photoresponse of graphene ruthenium-complex heterostructures
The aim of this study is to understand the photoresponse of a Ruthenium-complex/graphene heterostructure. Early work demonstrated that light detection by graphene field effect devices was enhanced by dropcasting Ruthenium Complex molecules. Here we proposed to fabricate a new class of devices where the Ruthenium-complex molecules are embedded between two layer of CVD monolayer graphene.
Photocurrent generation in Graphene Field Effect Transistors (GFETs)
In this work, we focused on the study of Graphene Field Effect Transistors (GFETs) photoelectrical response due to the combination of photovoltaic and photo-thermoelectric effects. The technological steps for the transistors fabrication together with their electro-optic response will be presented. Measurements were performed by using a 405 nm laser diode with AM modulation at 1.33 KHz shined onto the sample under test. GFETs electrical output signals were measured by using a lock-in amplifier synchronized to the same reference frequency of the laser driver. This gave us the possibility to evaluate the optical characteristics as a function of both the incident laser power and the static pola…
Fabrication and characterization of graphene field effect transistors (GFET)
Graphene is a flat monolayer of carbon atoms tightly packed into a two-dimensional (2D) honeycomb lattice. This peculiarity is responsible of extraordinary physical properties. Graphene exhibits a strong ambipolar field effect and thanks to its huge charge carrier mobility, graphene is a suitable material for high frequency Electronics. Graphene field effect transistors (GFET) for high frequency applications have recently received much attention and significant progress has been achieved in this area. GFETs have been already made by using pre-patterned metal or graphene nanoribbon (GNR) back-gates and hexagonal boron nitride as a dielectric spacer. Among the most employed techniques for the…
Microwave parameters dependence on Graphene Field Effect Transistors (GFETs) dimensions
Graphene is a relatively new material whose unique properties have attracted significant interest for its use in electronic and photonic applications. In particular, field effect has been proved in graphene samples and this feature, together with the high carrier mobility observed, makes graphene an interesting solution for high frequency electronics. In our work, we performed a statistical analysis in order to evaluate the microwave parameters dependence on Graphene Field Effect Transistors (GFETs) dimensions. In more detail, for the first time, we studied the behavior of the cut-off frequency (ft) and of the output impedance (Zout) at varying both the gate-drain/gate-source distance (Δ) a…
Infrared detection in multifunctional graphene-based transistors
In the last years great attention has been paid to graphene-based devices for optoelectronic applications such as photodetection. In this work, we report on Graphene Field Effect Transistors (GFETs) photoelectrical response due to the photo-transistor effect. Photoelectrical measurements were performed using a 1.55 μm erbium fiber laser. Optical measurements as a function of both the incident laser power and the DC bias of the fabricated devices have been carried out and show that photocurrent increases with the power of the IR beam illuminating the sample.