Unveiling the impact of the bias-dependent charge neutrality point on graphene based multi-transistor applications

Abstract

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.

Compact Modeling of pH-Sensitive FETs Based on 2-D Semiconductors

“…In the subthreshold region, the drain current has exponential dependence on the gate voltage reaching 731 (131) for the MoS2-(ReS2-)ISFET, while in saturation and linear regions the relationship becomes quadratic and linear [25], with values of 47 (30) and 14 (14), respectively. These predictions are in excellent agreement to those experimentally achieved: 713 (126), 53 (35) and 13 (14) in [4] ( [5]). In addition, we have employed this model to determine the change of drain current as a function of the pH in the subthreshold region (Figs.…”

“…This is consistent with the results achieved by Le et al in [28], who demonstrated a measured SpH-V of 4.4 V/pH for γ = 33 for the particular case of monolayer MoS2-based ISFETs. * Rc represents the metal-2D semiconductor contact resistance, included by connecting lumped resistors to the drain and source terminals [35].…”

Modelos De Microondas Para Dispositivos Ambipolares De Grafeno

“…Fuente: (Pasadas et al, 2021) Aunque este trabajo se centra en los GFET, los diseños de RF específicos se pueden adoptar para otras tecnologías 2D ambipolares, como el fosforeno (Das et al, 2014) o los FET MoTe2 (Lin et al, 2014), entre otros. A continuación, resumimos las principales aplicaciones de los GFET en circuitos de RF para la enseñanza en ingeniería.…”

“…Para un GFET de canal largo con buen comportamiento, podemos estimar V Dirac de acuerdo con la Ref. (Pasadas et al, 2021) como:…”

“…Cada GFET se describe en la Tabla I. Se propone la inclusión de una resistencia, R X , entre dos GFET en cascada para originar características de transferencia en forma de W que pueden aprovecharse para la multiplicación de frecuencia de acuerdo con (Pasadas et al, 2021). Principio de funcionamiento para el triplicador de frecuencia basado en GFET (izquierda) y cuadruplicador (derecha) basado en el TC en V DD =2V y R X =1kΩ.…”