transistor channel
Recently Published Documents


TOTAL DOCUMENTS

98
(FIVE YEARS 16)

H-INDEX

18
(FIVE YEARS 1)

Coatings ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 57
Author(s):  
Md Maruful Islam ◽  
Toshiyuki Yoshida ◽  
Yasuhisa Fujita

Various annealing atmospheres were employed during our unique thermal-diffusion type Ga-doping process to investigate the surface, structural, optical, and electrical properties of Ga-doped zinc oxide (ZnO) nanoparticle (NP) layers. ZnO NPs were synthesized using an arc-discharge-mediated gas evaporation method, followed by Ga-doping under open-air, N2, O2, wet, and dry air atmospheric conditions at 800 °C to obtain the low resistive spray-coated NP layers. The I–V results revealed that the Ga-doped ZnO NP layer successfully reduced the sheet resistance in the open air (8.0 × 102 Ω/sq) and wet air atmosphere (8.8 × 102 Ω/sq) compared with un-doped ZnO (4.6 × 106 Ω/sq). Humidity plays a key role in the successful improvement of sheet resistance during Ga-doping. X-ray diffraction patterns demonstrated hexagonal wurtzite structures with increased crystallite sizes of 103 nm and 88 nm after doping in open air and wet air atmospheres, respectively. The red-shift of UV intensity indicates successful Ga-doping, and the atmospheric effects were confirmed through the analysis of the defect spectrum. Improved electrical conductivity was also confirmed using the thin-film-transistor-based structure. The current controllability by applying the gate electric-field was also confirmed, indicating the possibility of transistor channel application using the obtained ZnO NP layers.


Author(s):  
Oleksii Yanenko ◽  
Leonid Virchenko

Problems. It is noted that the measurement of low-intensity microwave signals of various physical bodies and biological objects is associated with the need to provide high sensitivity, which can reach 10-14 -10-15 watts. The authors of the article studied the selective (selective) filter-amplifier of the switching frequency of the high-sensitivity modulation radiometer as one of the elements that have a significant impact on the sensitivity and accuracy of measurement, and developed recommendations for improving the stability of its parameters. The purpose of the research. The peculiarities of the modulation radiometer conversion channel operation are considered and the role of the selective switching frequency amplifier in providing such sensitivity is determined. The input and output signals of the selective amplifier, their relationship and the effect on the sensitivity of the radiometer were obtained and analyzed. The necessity of application of compensation of influence of temperature on characteristics of the filter taking into account temperature coefficients of elements of the scheme is proved. Conclusions. Modeling of a selective amplifier with a third-order filter was performed, the amplitude-frequency characteristic and the zone of its possible displacement at the maximum operating temperature were obtained. The structural and schematic diagram of the selective amplifier with automatic consideration of temperature influences, due to the introduction of feedback and correction of the frequency response of the filter has been developed. The main parameters of the bandpass filter built on the feedback circuit are determined. The use of a field-effect transistor channel connected in series with the resistors of the frequency-forming circuits of the third-order filter is proposed as an element of frequency response correction. The technical requirements for modeling and development of a selective amplifier are determined, which provide opportunities for implementation in practice. The research can be used to build a highly sensitive radiometric system for measuring low-intensity signals in areas such as biology and medicine.


2021 ◽  
Vol 23 (4) ◽  
pp. 179-185
Author(s):  
A.I. Khlybov ◽  
◽  
D.V. Rodionov ◽  
A.I. Panteleev ◽  
P.V. Timoshenkov ◽  
...  

This paper contains research results of thermal process in power GaN RF transistor in silicon substrate for pulse mode. Thermal mode research was done using computer simulation. Authors developed methodic allows significant decrease computational complexity. The dependences of maximum transistor channel temperature and thermal resistance as function of pulse width (with constant duty cycle) were done. Thermal simulation was done for power GaN RF transistor with overall gate width 2.1 mm.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sotirios Papamatthaiou ◽  
Pedro Estrela ◽  
Despina Moschou

AbstractLab-on-Chip is a technology that aims to transform the Point-of-Care (PoC) diagnostics field; nonetheless a commercial production compatible technology is yet to be established. Lab-on-Printed Circuit Board (Lab-on-PCB) is currently considered as a promising candidate technology for cost-aware but simultaneously high specification applications, requiring multi-component microsystem implementations, due to its inherent compatibility with electronics and the long-standing industrial manufacturing basis. In this work, we demonstrate the first electrolyte gated field-effect transistor (FET) DNA biosensor implemented on commercially fabricated PCB in a planar layout. Graphene ink was drop-casted to form the transistor channel and PNA probes were immobilized on the graphene channel, enabling label-free DNA detection. It is shown that the sensor can selectively detect the complementary DNA sequence, following a fully inkjet-printing compatible manufacturing process. The results demonstrate the potential for the effortless integration of FET sensors into Lab-on-PCB diagnostic platforms, paving the way for even higher sensitivity quantification than the current Lab-on-PCB state-of-the-art of passive electrode electrochemical sensing. The substitution of such biosensors with our presented FET structures, promises further reduction of the time-to-result in microsystems combining sequential DNA amplification and detection modules to few minutes, since much fewer amplification cycles are required even for low-abundance nucleic acid targets.


2021 ◽  
Author(s):  
Mehrdad Rostami Osanloo ◽  
Maarten Van de Put ◽  
Ali Saadat ◽  
William Vandenberghe

Abstract Two-dimensional (2D) van der Waals (vdW) materials promise ideal electrostatic control of charge carrier flow in a channel free of surface roughness or defects. To realize this ideal, good vdW dielectrics are needed in addition to the well explored channel materials. We study the dielectric properties of 32 easily exfoliable vdW materials using first principles methods. Specifically, we calculate the static and optical dielectric response of the monolayer and bulk form. In monolayers, we discover a strong out-of-plane response in GeClF (10.99), LaOBr (13.20), LaOCl (55.80) and PbClF (15.17), while the in-plane dielectric response is strong in BiOCl, PbClF, and TlF, ranging from 64.86 to 98.37. To assess their potential as gate dielectrics, we calculate the bandgap and electron affinity, and estimate the leakage current through the dielectric. We discover seven monolayer 2D dielectrics that promise to outperform bulk HfO2: LaOBr, LaOCl, CaHI, SrBrF, SrHBr, SrHI, and TlF with lower leakage currents at a significantly reduced equivalent oxide thickness. Of these, LaOBr and LaOCl are the most promising and our findings motivate the growth and exfoliation of rare-earth oxyhalides for their use as vdW dielectrics on vdW transistor channel materials.


Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 688
Author(s):  
Jaime Calvo-Gallego ◽  
Juan A. Delgado-Notario ◽  
Jesús E. Velázquez-Pérez ◽  
Miguel Ferrando-Bataller ◽  
Kristel Fobelets ◽  
...  

This paper reports on a study of the response of a T-gate strained-Si MODFETs (modulation-doped field-effect transistor) under continuous-wave sub-THz excitation. The sub-THz response was measured using a two-tones solid-state source at 0.15 and 0.30 THz. The device response in the photovoltaic mode was non-resonant, in agreement with the Dyakonov and Shur model for plasma waves detectors. The maximum of the photoresponse was clearly higher under THz illumination at 0.15 THz than at 0.3 THz. A numerical study was conducted using three-dimensional (3D) electromagnetic simulations to delve into the coupling of THz radiation to the channel of the transistor. 3D simulations solving the Maxwell equations using a time-domain solver were performed. Simulations considering the full transistor structure, but without taking into account the bonding wires used to contact the transistor pads in experiments, showed an irrelevant role of the gate length in the coupling of the radiation to the device channel. Simulations, in contradiction with measurements, pointed to a better response at 0.3 THz than under 0.15 THz excitation in terms of the normalized electric field inside the channel. When including four 0.25 mm long bonding wires connected to the contact pads on the transistor, the normalized internal electric field induced along the transistor channel by the 0.15 THz beam was increased in 25 dB, revealing, therefore, the important role played by the bonding wires at this frequency. As a result, the more intense response of the transistor at 0.15 THz than at 0.3 THz experimentally found, must be attributed to the bonding wires.


2020 ◽  
Author(s):  
Keying Guo ◽  
Shofarul Wustoni ◽  
Anil Koklu ◽  
Escarlet Díaz-Galicia ◽  
Maximilian Moser ◽  
...  

AbstractThe COVID-19 pandemic highlights the need for rapid protein detection and quantification at the single-molecule level in a format that is simple and robust enough for widespread point-of-care applications. We here introduce a modular nanobody-organic electrochemical transistor architecture that enables the fast and specific detection and quantification of single-molecule to nanomolar protein antigen concentrations in complex bodily fluids. The sensor combines a new solution-processable organic semiconductor material in the transistor channel with the high-density and orientation-controlled bioconjugation of nanobody fusion proteins on disposable gate electrodes. It provides results after a 10 minutes exposure to 5 µL of unprocessed samples, maintains high specificity and single-molecule sensitivity in human saliva or serum, and is rapidly reprogrammed towards any protein target for which nanobodies exist. We demonstrate the use of this highly modular platform for the detection of green fluorescent protein, SARS-CoV-1/2, and MERS-CoV spike proteins and validate the sensor for COVID-19 screening in unprocessed clinical nasopharyngeal swab and saliva samples.


2020 ◽  
Vol 11 ◽  
pp. 1329-1335
Author(s):  
Jakub Jadwiszczak ◽  
Pierce Maguire ◽  
Conor P Cullen ◽  
Georg S Duesberg ◽  
Hongzhou Zhang

Helium ion irradiation is a known method of tuning the electrical conductivity and charge carrier mobility of novel two-dimensional semiconductors. Here, we report a systematic study of the electrical performance of chemically synthesized monolayer molybdenum disulfide (MoS2) field-effect transistors irradiated with a focused helium ion beam as a function of increasing areal irradiation coverage. We determine an optimal coverage range of approx. 10%, which allows for the improvement of both the carrier mobility in the transistor channel and the electrical conductance of the MoS2, due to doping with ion beam-created sulfur vacancies. Larger areal irradiations introduce a higher concentration of scattering centers, hampering the electrical performance of the device. In addition, we find that irradiating the electrode–channel interface has a deleterious impact on charge transport when contrasted with irradiations confined only to the transistor channel.


Author(s):  
Е.А. Тарасова ◽  
С.В. Оболенский ◽  
C.В. Хазанова ◽  
Н.Н. Григорьева ◽  
О.Л. Голиков ◽  
...  

Abstract The nonlinearity of the gate–drain current–voltage characteristics in classical Schottky transistors and two-dimensional electron gas field-effect transistors based on AlGaAs/InGaAs/GaAs and InGaAs/GaAs compounds is analyzed. The carrier velocity-overshoot effect in the transistor channel is analyzed for various doping profiles of the structures under study.


Sign in / Sign up

Export Citation Format

Share Document