Compact Modeling Technology for the Simulation of Integrated Circuits Based on Graphene Field-Effect Transistors

The progress made toward the definition of a modular compact modeling technology for graphene field-effect transistors (GFETs) that enables the electrical analysis of arbitrary GFET-based integrated circuits is reported. A set of primary models embracing the main physical principles defines the ideal GFET response under DC, transient (time domain), AC (frequency domain), and noise (frequency domain) analysis. Another set of secondary models accounts for the GFET non-idealities, such as extrinsic-, short-channel-, trapping/detrapping-, self-heating-, and non-quasi static-effects, which can have a significant impact under static and/or dynamic operation. At both device and circuit levels, significant consistency is demonstrated between the simulation output and experimental data for relevant operating conditions. Additionally, a perspective of the challenges during the scale up of the GFET modeling technology toward higher technology readiness levels while drawing a collaborative scenario among fabrication technology groups, modeling groups, and circuit designers, is provided.European Commission 881603Spanish Government European Commission RTI2018-097876-B-C21 European CommissionDepartament de Recerca i Universitat 001-P-00170

Two-dimensional tellurium-based diodes for RF applications

The research of two-dimensional (2D) Tellurium (Te) or tellurene is thriving to address current challenges in emerging thin-film electronic and optoelectronic devices. However, the study of 2D-Te-based devices for high-frequency applications is still lacking in the literature. This work presents a comprehensive study of two types of radio frequency (RF) diodes based on 2D-Te flakes and exploits their distinct properties in two RF applications. First, a metal-insulator-semiconductor (MIS) structure is employed as a nonlinear device in a passive RF mixer, where the achieved conversion loss at 2.5 GHz and 5 GHz is as low as 24 dB and 29 dB, respectively. Then, a metal-semiconductor (MS) diode is tested as a zero-bias millimeter-wave power detector and reaches an outstanding linear-in-dB dynamic range over 40 dB, while having voltage responsivities as high as 257 V ⋅ W−1 at 1 GHz (up to 1 V detected output voltage) and 47 V ⋅ W−1 at 2.5 GHz (up to 0.26 V detected output voltage). These results show superior performance compared to other 2D material-based devices in a much more mature technological phase. Thus, the authors believe that this work demonstrates the potential of 2D-Te as a promising material for devices in emerging high-frequency electronics.MCIN/AEI/10.13039/501100011033European Union NextGenerationEU/PRTRGerman Research Foundation (DFG) under the projects GLECS2 (No. 653408)MOSTFLEX (653414),The Natural Sciences and Engineering Research Council (NSERC) (RGPIN-2017-05810 and ALLRP 577611-22)The European Commission under the Horizon 2020 projects Graphene Flagship (No. 785219 and 881603)PAIDI 2020 and European Social Fund Operational Programme 2014-2020 no. 20804Ministerio de UniversidadesGrant no. CAS21/ 00483Canada Foundation for Innovation (CFI)British Columbia Knowledge Development Fund (BCKDF)Western Economic Diversification Canada (WD)Simon Fraser Universit

Microwave Models for Graphene Ambipolar Devices: an Engineering Teaching Perspective

In this article it iimplemented a set of circuit models to be exploited in conventional circuit simulators used in engineering degrees. The models capture the physics of the graphene-based transistors, characterized by the ambipolar conduction, and its resulting V-shaped transfer characteristics (current vs. gate voltage). These models can be exploited by the engineering students to explore ambipolar electronics opening the possibility to 1) redesigning and simplifying of conventional circuits; and 2)seeking of new functionalities in both analogue/RF and digital domains. In thisregard, as an example by just considering that the V-shaped transfer characteristicsbehaves as a parabola, we present new insights for the design of graphene-based RFpower amplifiers, mixers, phase shifters and frequency multipliers that specificallyEn este trabajo, se implementan un conjunto de modelos que resuelven la física de los transistores basados en grafeno, capturando la conducción ambipolar y proporcionando las peculiares curvas de corriente frente a voltaje de puerta con forma de “V”. Estas herramientas pueden ser potencialmente utilizadas por estudiantes de ingeniería para explorar la electrónica ambipolar, abriendo la posibilidad de 1) rediseñar y simplificar aplicaciones de microondas convencionales; y 2) buscar nuevas funcionalidades en el ámbito analógico y de alta frecuencia. A este respecto, como ejemplo, presentamos nuevos enfoques para el diseño de multiplicadores de frecuencia, amplificadores de potencia, mezcladores y desfasadores en radiofrecuencia que específicamente aprovechan la ambipolaridadPAIDI 2020 y de European Social Fund Operational Programme 2014–2020 no. 20804Contrato PTA, con referencia PTA2020-018250-

A Novel Analysis of Periodic Structures Based on Loaded Transmission Lines

Periodically loaded transmission lines are characterized by a frequency response with regular pass and stopbands. Interestingly, each of the passbands exhibits a peculiar comb-alike behavior, in which again, nested (or internal) pass and stopbands can be identified. In this work, we focus our attention on the effect that changing the characteristics of the periodic load (which is a varactor capacitance in our case) has in this peculiar response of the structure, providing a novel and detailed analysis of such bands. The control of the response of the structure when changing the properties of the load allows to adjust the transmission characteristics of the circuit once it is fabricated. To this purpose, we derive the design equations of the periodically loaded structures, obtaining the expressions which govern the position and number of the transmission peaks, i.e., the points where |S21| = 1 for both cases, the frequency sweep and the capacitance sweep. We experimentally validate our analysis by fabricating a periodic structure with five unit cells and compare the measurements against both theoretical results and circuit simulations to an excellent agreement. The present analysis paves the way towards further exploitation of these kind of structures for the design of different microwave applications such as tunable filters or phase shiftersMCIN/AEI/PTA grantPTA2020-018250-IPAIDI 2020European Social Fund Operational Programme 2014-2020 under Grant 20804Ministerio de Universidades under Grant CAS21/00483FEDER/Junta de Andalucía-Consejería de Transformación Económica, Industria, Conocimiento y Universidades under Grants A-TIC-646-UGR20, B-RNM-375-UGR18P20_00633MCIN/AEI/10.13039/501100011033European Union “NextGenerationEU”/PRTRPID2020-116518GB-I00TED2021-129769B-I00TED2021-129938B-I0

Reconfigurable frequency multipliers based on graphene field‑effect transistors

This work is part of the research project P21_00149 ENERGHENE funded by Consejería de Universidad, Investigación e Innovación de la Junta de Andalucía. This work is also supported by FEDER/Junta de Andalucía - Consejería de Transformación Económica, Industria, Conocimiento y Universidades through the projects P20-00633 and A-TIC-646-UGR20, by Spanish Government through projects PID2020-116518GBI00 funded by MCIN/AEI/10.13039/501100011033 and TED2021-129769B-I00 funded by MCIN/AEI/10.13039/501100011033 and the European Union NextGenerationEU/PRTR. F. Pasadas acknowledges funding from PAIDI 2020 and the European Social Fund Operational Programme 2014-2020 no. 20804. M. D. Ganeriwala acknowledges funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 101032701.Supplementary information The online version contains supplementary material available at (https://doi.org/10.1186/s11671-023-03884-8).Run-time device-level reconfigurability has the potential to boost the performance and functionality of numerous circuits beyond the limits imposed by the integration density. The key ingredient for the implementation of reconfigurable electronics lies in ambipolarity, which is easily accessible in a substantial number of two-dimensional materials, either by contact engineering or architecture device-level design. In this work, we showcase graphene as an optimal solution to implement high-frequency reconfigurable electronics. We propose and analyze a split-gate graphene field-effect transistor, demonstrating its capability to perform as a dynamically tunable frequency multiplier. The study is based on a physically based numerical simulator validated and tested against experiments. The proposed architecture is evaluated in terms of its performance as a tunable frequency multiplier, able to switch between doubler, tripler or quadrupler operation modes. Different material and device parameters are analyzed, and their impact is assessed in terms of the reconfigurable graphene frequency multiplier performance.Research project P21_00149 ENERGHENE funded by Consejería de Universidad, Investigación e Innovación de la Junta de AndalucíaFEDER/Junta de Andalucía - Consejería de Transformación Económica, Industria, Conocimiento y Universidades through the projects P20-00633 and A-TIC-646-UGR20Spanish Government through projects PID2020-116518GBI00MCIN/AEI/10.13039/501100011033European Union NextGenerationEU/PRTRPAIDI 2020 and the European Social Fund Operational Programme 2014-2020 no. 20804.European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 10103270

Variability Assessment of the Performance of MoS2-Based BioFETs

Two-dimensional material (2DM)-based Field-Effect Transistors (FETs) have been postulated as a solid alternative for biosensing applications thanks to: (i) the possibility to enable chemical sensitivity by functionalization, (ii) an atomically thin active area which guarantees optimal electrostatic coupling between the sensing layer and the electronic active region, and (iii) their compatibility with large scale fabrication techniques. Although 2DM-based BioFETs have demonstrated notable sensing capabilities, other relevant aspects, such as the yield or device-to-device variability, will demand further evaluation in order to move them from lab-to-fab applications. Here, we focus on the latter aspect by analyzing the performance of MoS2-based BioFETs for the detection of DNA molecules. In particular, we explore the impact of the randomized location and activation of the receptor molecules at the sensing interface on the device response. Several sensing interface configurations are implemented, so as to evaluate the sensitivity dependence on device-to-device variabilitySpanish Government PID2020-116518GB-I00 TED2021-129769B-I00FEDER/Junta de Andalucia A-TIC-646-UGR20 P20-00633European Commission European Commission Joint Research Centre 825213PAIDI 2020 grant 20804PTA grant PTA2020-018250-ISpanish Government FPU019/05132Plan Propio of Universidad de Granad

Exploiting ambipolarity in graphene field-effect transistors for novel designs on high-frequency analog electronics

This work was funded by FEDER/Junta de Andalucía-Consejería de Transformación Económica, Industria, Conocimiento y Universidades through the Projects A-TIC-646-UGR20, B-RNM-375-UGR18 and P20_00633; by Junta de Andalucía-Consejería de Universidad, Investigación e Innovación under ENERGHENE Project No. P21_00149; and by MCIN/AEI/10.13039/501100011033 through the projects PID2020- 116518GB-I00 and PID2021-127840NB-I00 (MCIN/AEI/FEDER, UE). The authors also acknowledge the support by the European Union’s Horizon 2020 Framework Programme for Research and Innovation through the Project GrapheneCore3 under Grant Agreement No. 881603. F.P. acknowledges funding from PAIDI 2020 – European Social Fund Operational Programme 2014–2020 No. 20804. A.M. acknowledges the support of the MCIN/AEI/PTA grant, with reference PTA2020-018250-I. M.C.P. acknowledges the FPU program with reference FPU21/04904. A.P.-S. acknowledges the support from Ministerio de Ciencia, Innovación y Universidades under Grant Agreement No. FJC2020-046213-I. E.R.-G. acknowledges the support from IPN Contract No. SIP/20230362. Funding for open access charge: Universidad de Granada / CBUA.Exploiting ambipolar electrical conductivity based on graphene field-effect transistors has raised enormous interest for high-frequency (HF) analog electronics. Controlling the device polarity, by biasing the graphene transistor around the vertex of the V-shaped transfer curve, enables to redesign and highly simplify conventional analog circuits, and simultaneously to seek for multifunctionalities, especially in the HF domain. This study presents new insights for the design of different HF applications such as power amplifiers, mixers, frequency multipliers, phase shifters, and modulators that specifically leverage the inherent ambipolarity of graphene-based transistors.FEDER/Junta de Andalucía-Consejería de Transformación Económica, Industria, Conocimiento y Universidades through the Projects A-TIC-646-UGR20, B-RNM-375-UGR18 and P20_00633Junta de Andalucía-Consejería de Universidad, Investigación e Innovación under ENERGHENE Project No. P21_00149MCIN/AEI/10.13039/501100011033 through the projects PID2020- 116518GB-I00 and PID2021-127840NB-I00 (MCIN/AEI/FEDER, UE)European Union’s Horizon 2020 Framework Programme for Research and Innovation through the Project GrapheneCore3 under Grant Agreement No. 881603PAIDI 2020 – European Social Fund Operational Programme 2014–2020 No. 20804MCIN/AEI/PTA grant, with reference PTA2020-018250-IFPU21/04904Ministerio de Ciencia, Innovación y Universidades under Grant Agreement No. FJC2020-046213-IIPN Contract No. SIP/20230362Funding for open access charge: Universidad de Granada / CBU

Graphene-on-Silicon Hybrid Field-Effect Transistors

The combination of graphene and silicon in hybrid electronic devices has attracted increasing attention over the last decade. Here, a unique technology of graphene-on-silicon heterostructures as solution-gated transistors for bioelectronics applications is presented. The proposed graphene-onsilicon field-effect transistors (GoSFETs) are fabricated by exploiting various conformations of channel doping and dimensions. The fabricated devices demonstrate hybrid behavior with features specific to both graphene and silicon, which are rationalized via a comprehensive physics-based compact model which is purposely implemented and validated against measured data. The developed theory corroborates that the device hybrid behavior can be explained in terms of two independent silicon and graphene carrier transport channels, which are, however, strongly electrostatically coupled. Although GoSFET transconductance and carrier mobility are found to be lower than in conventional silicon or graphene field-effect transistors, it is observed that the combination of both materials within the hybrid channel contributes uniquely to the electrical response. Specifically, it is found that the graphene sheet acts as a shield for the silicon channel, giving rise to a nonuniform potential distribution along it, which impacts the transport, especially at the subthreshold region, due to non-negligible diffusion current.MCIN/AEI PID2020-116518GB-I00FEDER/Junta de Andalucia-Consejeria de Transformacion Economica, Industria, Conocimiento y Universidades A-TIC-646-UGR20 B-RNM-375-UGR18 PY20_00633European Commission 825213PAIDI 2020European Social Fund Operational Programme 2014-2020 20804MCIN/AEI/PTA grant PTA2020-018250-IProjekt DEA