Topic Editors

National Institute for R&D in Microtechnologies—IMT Bucharest, Strada Erou Iancu Nicolae 126A, 077190 Voluntari, Romania
National Institute of Materials Physics, 405A Atomistilor Street, 077125 Magurele, Romania
Research Centre for Integrated Systems Nanotechnologies and Carbon Based Nanomaterials (CENASIC), National Institute for Research and Development in Microtechnologies (IMT Bucharest), 077190 Bucharest, Romania
National Institute for Research and Development in Microtechnologies, IMT Bucharest, 077190 Voluntari, Romania

Modeling, Fabrication, and Characterization of Semiconductor Materials and Devices

Abstract submission deadline
closed (20 February 2024)
Manuscript submission deadline
closed (15 May 2024)
Viewed by
30136

Topic Information

Dear Colleagues,

Semiconductor devices are central to the modern digital economy, from smartphones and cars to critical applications and infrastructures for healthcare, energy, mobility, communications and industrial automation. They are a crucial element for the development of future technology, including artificial intelligence (AI), 5G communications and computing. The semiconductor field is one of the most fast-paced areas of research and development. Therefore, determining the right set of processes, selecting the right chemicals and materials and employing cutting-edge data analytics software and the most reliable technology solutions are central to its over-expanding success and for reinvestment back into the R&D cycle.

For almost 50 years, the International Semiconductors Conference (https://www.imt.ro/cas) has tackled different aspects of the semiconductor value chain, targeting not only semiconductor electronics but also micro-and nanotechnologies (including micro-nanosystems). Conference participants, as well as relevant scholars (non-participants), are welcome to contribute.

The topics of interest for this project include (but are not restricted to):

- Nanoscience and Nanoengineering;
- Micro- and nanophotonics and Optoelectronics;
- Microwave and Millimeter Wave Circuits and Systems;
- Microsensors and Microsystems;
- Modeling;
- Semiconductor Devices;
- Integrated Circuits.

Dr. Andrei Avram
Dr. Ana-Maria Lepadatu
Dr. Florin Nastase
Dr. Martino Aldrigo
Topic Editors

Keywords

  • micro- and nanotechnologies
  • semiconductor devices modeling
  • simulation
  • micro- and nanophotonics 
  • optoelectronics

Participating Journals

Journal Name Impact Factor CiteScore Launched Year First Decision (median) APC
Coatings
coatings
2.9 5.0 2011 13.7 Days CHF 2600
Electronics
electronics
2.6 5.3 2012 16.8 Days CHF 2400
Journal of Sensor and Actuator Networks
jsan
3.3 7.9 2012 22.6 Days CHF 2000
Nanomaterials
nanomaterials
4.4 8.5 2010 13.8 Days CHF 2900
Sensors
sensors
3.4 7.3 2001 16.8 Days CHF 2600

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Published Papers (20 papers)

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9 pages, 6245 KiB  
Article
Mid-Infrared Emission in Ge/Ge1-xSnx/Ge Quantum Well Modeled Within 14-Band k.p Model
by Omar Zitouni, Nouha Mastour and Said Ridene
Electronics 2024, 13(21), 4142; https://doi.org/10.3390/electronics13214142 - 22 Oct 2024
Viewed by 654
Abstract
Band structure and gain in a Ge/Ge1-xSnx/Ge quantum well are described theoretically using a 14-band k.p model. It has been shown that the quantum well width and the α-Sn concentration considerably modify the conduction and valence subband structure, and, [...] Read more.
Band structure and gain in a Ge/Ge1-xSnx/Ge quantum well are described theoretically using a 14-band k.p model. It has been shown that the quantum well width and the α-Sn concentration considerably modify the conduction and valence subband structure, and, as a result, the optical gain changes with the insertion of a very small concentration of α-Sn. In particular, we have determined the necessary injection carrier density Nj and the critical α-Sn concentration for elevated high gain lasing. It is found that for Nj = 1.5 × 1018 cm−3, we achieved a maximum peak gain for α-Sn concentration of the order 0.155. We can predict that Ge/Ge1-xSnx/Ge QWs should be manufactured with an α-Sn concentration less than 0.155 in devices for optoelectronics applications such as telecommunication and light emitting laser diodes. Full article
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22 pages, 7975 KiB  
Article
Low-Cost Source Measure Unit (SMU) to Characterize Sensors Built on Graphene-Channel Field-Effect Transistors
by Ashley Morgan Galanti and Mark A. Haidekker
Sensors 2024, 24(12), 3841; https://doi.org/10.3390/s24123841 - 14 Jun 2024
Viewed by 1021
Abstract
This study introduces a flexible and low-cost solution for a source measure unit (SMU), which is presented as an alternative to conventional source meter units and a blueprint for sensor FET drivers. An SMU collects current–voltage (I-V) curves with an additional variable voltage [...] Read more.
This study introduces a flexible and low-cost solution for a source measure unit (SMU), which is presented as an alternative to conventional source meter units and a blueprint for sensor FET drivers. An SMU collects current–voltage (I-V) curves with an additional variable voltage or current and is commonly used to characterize semiconductors. We present the hardware design, interfacing, and test results of our SMU. Specifically, we present representative I-V curve measurements for graphene-channel FETs to demonstrate the SMU’s capability to efficiently characterize these devices with minimal noise and sufficient accuracy. This cost-effective solution presents a promising avenue for researchers and developers seeking reliable tools for sensor development and characterization. We demonstrate, with the example of surface illumination, how the sensing behavior of graphene-channel FETs can be characterized without the need for expensive equipment. Additionally, the SMU was validated with known passive and active components, along with probe station integration for semiconductor die-scale connection. The SMU’s focus on collecting I-V curves, coupled with its ability to identify device defects, such as parasitic Schottky junctions or a failed oxide, contributes to its utility in quality testing for semiconductor devices. Its low-cost nature makes it accessible for various research endeavors, enabling efficient data collection and analysis for graphene-based and other nanomaterial-based sensor applications. Full article
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10 pages, 2534 KiB  
Article
Electron-Induced Single-Event Effect in 28 nm SRAM-Based FPGA
by Jiayu Tian, Rongxing Cao, Yan Liu, Yulong Cai, Bo Mei, Lin Zhao, Shuai Cui, He Lv and Yuxiong Xue
Electronics 2024, 13(12), 2233; https://doi.org/10.3390/electronics13122233 - 7 Jun 2024
Cited by 1 | Viewed by 844
Abstract
As the feature size of integrated circuit decreases, the critical charge of single-event effect decreases as well, making nano-scale devices more susceptible to the high-energy charged particles during their application in space. Here, we study the electron-induced single-event effect in 28 nm static [...] Read more.
As the feature size of integrated circuit decreases, the critical charge of single-event effect decreases as well, making nano-scale devices more susceptible to the high-energy charged particles during their application in space. Here, we study the electron-induced single-event effect in 28 nm static random-access memory (SRAM)-based field programmable gate array (FPGA) utilizing high-energy electrons with energy of 1 MeV~5 MeV. The experimental results demonstrate that the 3 MeV electrons can cause single-event functional interrupts (SEFIs) in FPGA, while the electrons with other energies cannot. To further explore the mechanism of electron-induced SEFIs in this nanoscale FPGA, we combined Monte Carlo, Technology Computer-Aided Design (TCAD), and Simulation Program with Integrated Circuit Emphasis (SPICE) simulations. It is revealed that the SEFI was mainly caused by the direct ionization effect of high-energy electrons, and the SEFI was related to the interactions between multiple sensitive nodes. Full article
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12 pages, 3869 KiB  
Article
Defect Analysis in a Long-Wave Infrared HgCdTe Auger-Suppressed Photodiode
by Małgorzata Kopytko, Kinga Majkowycz, Krzysztof Murawski, Jan Sobieski, Waldemar Gawron and Piotr Martyniuk
Sensors 2024, 24(11), 3566; https://doi.org/10.3390/s24113566 - 1 Jun 2024
Viewed by 760
Abstract
Deep defects in the long-wave infrared (LWIR) HgCdTe heterostructure photodiode were measured via deep-level transient spectroscopy (DLTS) and photoluminescence (PL). The n+-P+-π-N+ photodiode structure was grown by following the metal–organic chemical vapor deposition (MOCVD) technique on a GaAs [...] Read more.
Deep defects in the long-wave infrared (LWIR) HgCdTe heterostructure photodiode were measured via deep-level transient spectroscopy (DLTS) and photoluminescence (PL). The n+-P+-π-N+ photodiode structure was grown by following the metal–organic chemical vapor deposition (MOCVD) technique on a GaAs substrate. DLTS has revealed two defects: one electron trap with an activation energy value of 252 meV below the conduction band edge, located in the low n-type-doped transient layer at the π-N+ interface, and a second hole trap with an activation energy value of 89 meV above the valence band edge, located in the π absorber. The latter was interpreted as an isolated point defect, most probably associated with mercury vacancies (VHg). Numerical calculations applied to the experimental data showed that this VHg hole trap is the main cause of increased dark currents in the LWIR photodiode. The determined specific parameters of this trap were the capture cross-section for the holes of σp = 10−16–4 × 10−15 cm2 and the trap concentration of NT = 3–4 × 1014 cm−3. PL measurements confirmed that the trap lies approximately 83–89 meV above the valence band edge and its location. Full article
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11 pages, 4360 KiB  
Article
The Influence Mechanism of Quantum Well Growth and Annealing Temperature on In Migration and Stress Modulation Behavior
by Luyi Yan, Feng Liang, Jing Yang, Ping Chen, Desheng Jiang and Degang Zhao
Nanomaterials 2024, 14(8), 703; https://doi.org/10.3390/nano14080703 - 18 Apr 2024
Viewed by 1331
Abstract
This study explores the effects of growth temperature of InGaN/GaN quantum well (QW) layers on indium migration, structural quality, and luminescence properties. It is found that within a specific range, the growth temperature can control the efficiency of In incorporation into QWs and [...] Read more.
This study explores the effects of growth temperature of InGaN/GaN quantum well (QW) layers on indium migration, structural quality, and luminescence properties. It is found that within a specific range, the growth temperature can control the efficiency of In incorporation into QWs and strain energy accumulated in the QW structure, modulating the luminescence efficiency. Temperature-dependent photoluminescence (TDPL) measurements revealed a more pronounced localized state effect in QW samples grown at higher temperatures. Moreover, a too high annealing temperature will enhance indium migration, leading to an increased density of non-radiative recombination centers and a more pronounced quantum-confined Stark effect (QCSE), thereby reducing luminescence intensity. These findings highlight the critical role of thermal management in optimizing the performance of InGaN/GaN MQWs in LEDs and other photoelectronic devices. Full article
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11 pages, 4485 KiB  
Article
Enhancing the Performance of GaN-Based Light-Emitting Diodes by Incorporating a Junction-Type Last Quantum Barrier
by Jun Wang, Yiman Xu, Xiaofei Wang, Zuyu Xu and Maogao Gong
Electronics 2024, 13(7), 1399; https://doi.org/10.3390/electronics13071399 - 8 Apr 2024
Cited by 1 | Viewed by 1230
Abstract
In this paper, an n-i-p-type GaN barrier for the final quantum well, which is closest to the p-type GaN cap layer, is proposed for nitride light-emitting diodes (LEDs) to enhance the confinement of electrons and to improve the efficiency of hole injection. The [...] Read more.
In this paper, an n-i-p-type GaN barrier for the final quantum well, which is closest to the p-type GaN cap layer, is proposed for nitride light-emitting diodes (LEDs) to enhance the confinement of electrons and to improve the efficiency of hole injection. The performances of GaN-based LEDs with a traditional GaN barrier and with our proposed n-i-p GaN barrier were simulated and analyzed in detail. It was observed that, with our newly designed n-i-p GaN barrier, the performances of the LEDs were improved, including a higher light output power, a lower threshold voltage, and a stronger electroluminescence emission intensity. The light output power can be remarkably boosted by 105% at an injection current density of 100 A/cm2 in comparison with a traditional LED. These improvements originated from the proposed n-i-p GaN barrier, which induces a strong reverse electrostatic field in the n-i-p GaN barrier. This field not only enhances the confinement of electrons but also improves the efficiency of hole injection. Full article
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13 pages, 2098 KiB  
Article
A Compact Model of Carbon Nanotube Field-Effect Transistors for Various Sizes with Bipolar Characteristics
by Wentao Huang and Lan Chen
Electronics 2024, 13(7), 1355; https://doi.org/10.3390/electronics13071355 - 3 Apr 2024
Cited by 1 | Viewed by 1247
Abstract
Carbon nanotubes have excellent electrical properties and can be used as a new generation of semiconductor materials. This paper presents a compact model for carbon nanotube field-effect transistors (CNTFETs). The model uses a semi-empirical approach to model the current–voltage properties of CNTFETs with [...] Read more.
Carbon nanotubes have excellent electrical properties and can be used as a new generation of semiconductor materials. This paper presents a compact model for carbon nanotube field-effect transistors (CNTFETs). The model uses a semi-empirical approach to model the current–voltage properties of CNTFETs with gate lengths exceeding 100 nm. This study introduces an innovative approach by proposing physical parametric reference lengths (Lref), which facilitate the integration of devices of varying sizes into a unified modeling framework. Furthermore, this paper develops models for the bipolar properties of carbon nanotube devices, employing two distinct sets of model parameters for enhanced accuracy. The model offers a comprehensive analysis of the different capacitances occurring between the electrodes within the device. The simulation of the model shows good agreement with the experimental measurements, confirming the model’s validity. The model is implemented in the Verilog-A hardware description language, with the circuit being subsequently constructed and subjected to simulations via the HSPICE tool. The CNTFET-based inverter exhibits a gain of 7.022 and a delay time of 16.23 ps when operated at a voltage of 1.2 V. Full article
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11 pages, 5363 KiB  
Article
4H-SiC/SiO2 Interface Degradation in 1.2 kV 4H-SiC MOSFETs Due to Power Cycling Tests
by Dahui Yoo, MiJin Kim, Inho Kang and Ho-Jun Lee
Electronics 2024, 13(7), 1267; https://doi.org/10.3390/electronics13071267 - 28 Mar 2024
Viewed by 1146
Abstract
Power cycling tests (PCTs) assess the reliability of power devices by closely simulating their operating conditions. A PCT was performed on commercially available 1.2 kV 4H-SiC power metal–oxide–semiconductor field-effect transistors to observe its impact on the 4H-SiC/SiO2 interface. High-resolution transmission electron microscopy [...] Read more.
Power cycling tests (PCTs) assess the reliability of power devices by closely simulating their operating conditions. A PCT was performed on commercially available 1.2 kV 4H-SiC power metal–oxide–semiconductor field-effect transistors to observe its impact on the 4H-SiC/SiO2 interface. High-resolution transmission electron microscopy and electron energy loss spectroscopy measurements showed variations in the length of the 4H-SiC/SiO2 transition layer, depending on whether the device was power cycled. Moreover, the total resistance at Vg Vt in Rtot − (Vg-Vt)−1 graph increased to 16.5%, while it changed more radically to 47.3% at Vg Vt. The threshold voltage shifted negatively. These variations cannot be expected solely through the wearout of the package. Full article
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8 pages, 2448 KiB  
Communication
Effect of Temperature-Dependent Low Oxygen Partial Pressure Annealing on SiC MOS
by Qian Zhang, Nannan You, Jiayi Wang, Yang Xu, Kuo Zhang and Shengkai Wang
Nanomaterials 2024, 14(2), 192; https://doi.org/10.3390/nano14020192 - 15 Jan 2024
Cited by 1 | Viewed by 1431
Abstract
Oxygen post annealing is a promising method for improving the quality of the SiC metal oxide semiconductor (MOS) interface without the introduction of foreign atoms. In addition, a low oxygen partial pressure annealing atmosphere would prevent the additional oxidation of SiC, inhibiting the [...] Read more.
Oxygen post annealing is a promising method for improving the quality of the SiC metal oxide semiconductor (MOS) interface without the introduction of foreign atoms. In addition, a low oxygen partial pressure annealing atmosphere would prevent the additional oxidation of SiC, inhibiting the generation of new defects. This work focuses on the effect and mechanism of low oxygen partial pressure annealing at different temperatures (900–1250 °C) in the SiO2/SiC stack. N2 was used as a protective gas to achieve the low oxygen partial pressure annealing atmosphere. X-ray photoelectron spectroscopy (XPS) characterization was carried out to confirm that there are no N atoms at or near the interface. Based on the reduction in interface trap density (Dit) and border trap density (Nbt), low oxygen partial pressure annealing is proven to be an effective method in improving the interface quality. Vacuum annealing results and time of flight secondary ion mass spectrometry (ToF-SIMS) results reveal that the oxygen vacancy (V[O]) filling near the interface is the dominant annealing mechanism. The V[O] near the interface is filled more by O2 in the annealing atmosphere with the increase in temperature. Full article
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14 pages, 5322 KiB  
Article
How to Accurately Determine the Ohmic Contact Properties on n-Type 4H-SiC
by Clément Berger, Daniel Alquier and Jean-François Michaud
Electronics 2024, 13(1), 217; https://doi.org/10.3390/electronics13010217 - 3 Jan 2024
Cited by 1 | Viewed by 2520
Abstract
The electrical properties of ohmic contacts are classically investigated by using the transfer length method (TLM). In the literature, the TLM patterns are fabricated onto different substrate configurations, especially directly onto the 4H-SiC wafers. But, due to the high doping level of commercial [...] Read more.
The electrical properties of ohmic contacts are classically investigated by using the transfer length method (TLM). In the literature, the TLM patterns are fabricated onto different substrate configurations, especially directly onto the 4H-SiC wafers. But, due to the high doping level of commercial substrates, the current is not confined close to the contact and, in this case, the specific contact resistance (SCR) value is overestimated. In this article, we propose, by the means of simulations, to investigate the influence of the layer under the contact towards the estimation of the SCR. The simulation results highlight that, for an accurate determination of the SCR values, an isolation layer between the contact and the silicon carbide substrate is mandatory. Thus, we have determined the characteristics (doping level and thickness) of a suitable isolation layer compatible with SCR values ranging from 10−3 to 10−6 Ω·cm2. Full article
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9 pages, 1801 KiB  
Article
Phase of Topological Lattice with Leaky Guided Mode Resonance
by Heejin Choi, Seonyeong Kim, Markus Scherrer, Kirsten Moselund and Chang-Won Lee
Nanomaterials 2023, 13(24), 3152; https://doi.org/10.3390/nano13243152 - 16 Dec 2023
Viewed by 1411
Abstract
Topological nature in different areas of physics and electronics has often been characterized and controlled through topological invariants depending on the global properties of the material. The validity of bulk–edge correspondence and symmetry-related topological invariants has been extended to non-Hermitian systems. Correspondingly, the [...] Read more.
Topological nature in different areas of physics and electronics has often been characterized and controlled through topological invariants depending on the global properties of the material. The validity of bulk–edge correspondence and symmetry-related topological invariants has been extended to non-Hermitian systems. Correspondingly, the value of geometric phases, such as the Pancharatnam–Berry or Zak phases, under the adiabatic quantum deformation process in the presence of non-Hermitian conditions, are now of significant interest. Here, we explicitly calculate the Zak phases of one-dimensional topological nanobeams that sustain guided-mode resonances, which lead to energy leakage to a continuum state. The retrieved Zak phases show as zero for trivial and as π for nontrivial photonic crystals, respectively, which ensures bulk–edge correspondence is still valid for certain non-Hermitian conditions. Full article
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14 pages, 1611 KiB  
Article
Chemisorption and Surface Reaction of Hafnium Precursors on the Hydroxylated Si(100) Surface
by Truong Ba Tai, Jonghun Lim and Hyeyoung Shin
Coatings 2023, 13(12), 2094; https://doi.org/10.3390/coatings13122094 - 16 Dec 2023
Cited by 1 | Viewed by 1769
Abstract
Hafnium oxide (HfO2) is widely recognized as one of the most promising high-k dielectric materials due to its remarkable properties such as high permittivity, wide band gap, and excellent thermal and chemical stability. The atomic layer deposition (ALD) of HfO [...] Read more.
Hafnium oxide (HfO2) is widely recognized as one of the most promising high-k dielectric materials due to its remarkable properties such as high permittivity, wide band gap, and excellent thermal and chemical stability. The atomic layer deposition (ALD) of HfO2 has attracted significant attention in recent decades since it enables uniform and conformal deposition of HfO2 thin films on various substrates. In this study, we examined the initial surface reactions of a series of homoleptic hafnium precursors on hydroxylated Si(100) surfaces using density functional theory calculations. Our theoretical findings align with previous experimental studies, indicating that hafnium amides exhibit higher reactivity compared to other precursors such as hafnium alkoxides and hafnium halides in surface reactions. Interestingly, we found that the chemisorption and reactivity of hafnium precursors are considerably affected by their thermal stability and size. For alkoxide precursors, which have similar thermal stabilities, the size of alkoxide ligands is an important factor in determining their reactivity. Conversely, the reactivity of hafnium halides, which have ligands of similar sizes, is primarily governed by their thermal stability. These insights are valuable for understanding the surface reaction mechanisms of precursors on hydroxylated Si(100) surfaces and for designing new materials, particularly heteroleptic precursors, in future research. Full article
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18 pages, 9862 KiB  
Article
Investigation of Donor-like State Distributions in Solution-Processed IZO Thin-Film Transistor through Photocurrent Analysis
by Dongwook Kim, Hyeonju Lee, Kadir Ejderha, Youngjun Yun, Jin-Hyuk Bae and Jaehoon Park
Nanomaterials 2023, 13(23), 2986; https://doi.org/10.3390/nano13232986 - 21 Nov 2023
Viewed by 1205
Abstract
The density of donor-like state distributions in solution-processed indium–zinc-oxide (IZO) thin-film transistors (TFTs) is thoroughly analyzed using photon energy irradiation. This study focuses on quantitatively calculating the distribution of density of states (DOS) in IZO semiconductors, with a specific emphasis on their variation [...] Read more.
The density of donor-like state distributions in solution-processed indium–zinc-oxide (IZO) thin-film transistors (TFTs) is thoroughly analyzed using photon energy irradiation. This study focuses on quantitatively calculating the distribution of density of states (DOS) in IZO semiconductors, with a specific emphasis on their variation with indium concentration. Two calculation methods, namely photoexcited charge collection spectroscopy (PECCS) and photocurrent-induced DOS spectroscopy (PIDS), are employed to estimate the density of the donor-like states. This dual approach not only ensures the accuracy of the findings but also provides a comprehensive perspective on the properties of semiconductors. The results reveal a consistent characteristic: the Recombination–Generation (R-G) center energy ET, a key aspect of the donor-like state, is acquired at approximately 3.26 eV, irrespective of the In concentration. This finding suggests that weak bonds and oxygen vacancies within the Zn-O bonding structure of IZO semiconductors act as the primary source of R-G centers, contributing to the donor-like state distribution. By highlighting this fundamental aspect of IZO semiconductors, this study enhances our understanding of their charge-transport mechanisms. Moreover, it offers valuable insight for addressing stability issues such as negative bias illumination stress, potentially leading to the improved performance and reliability of solution-processed IZO TFTs. The study contributes to the advancement of displays and technologies by presenting further innovations and applications for evaluating the fundamentals of semiconductors. Full article
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12 pages, 2598 KiB  
Article
A Surface Potential Model for Metal-Oxide-Semiconductor Transistors Operating near the Threshold Voltage
by Hwang-Cherng Chow, Bo-Wen Lee, Shang-Ying Cheng, Yung-Hsuan Huang and Ruey-Dar Chang
Electronics 2023, 12(20), 4242; https://doi.org/10.3390/electronics12204242 - 13 Oct 2023
Viewed by 1343
Abstract
Device physics and accurate transistor modeling are necessary to reduce the operating voltage near the threshold for power-constrained circuits. Conventional device modeling for metal-oxide-semiconductor (MOS) transistors focuses on operations in either strong or weak inversion regimes, and the electrostatics at gate biases near [...] Read more.
Device physics and accurate transistor modeling are necessary to reduce the operating voltage near the threshold for power-constrained circuits. Conventional device modeling for metal-oxide-semiconductor (MOS) transistors focuses on operations in either strong or weak inversion regimes, and the electrostatics at gate biases near the threshold voltage is rarely studied. This research proposed an analytical model to describe the distribution of the surface potential along the channel for near-threshold operation. Numerical device simulations were also performed to investigate the electrostatics near the threshold voltage. The numerical simulation with constant carrier mobility showed an overshoot in the transconductance due to decay of the lateral electric field with gate bias. The decay of the lateral electric field was predicted by the proposed analytical surface potential model which considered widening the channel length with flooding of the inversion carriers in the channel and gate overlap regions. The channel length widening effect saturated as the gate bias further increased. Therefore, evident transconductance overshoot was observed near the threshold voltage in short-channel devices. Full article
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21 pages, 5078 KiB  
Article
Low-Temperature Predicted Structures of Ag2S (Silver Sulfide)
by Stanislav I. Sadovnikov, Maksim G. Kostenko, Aleksandr I. Gusev and Aleksey V. Lukoyanov
Nanomaterials 2023, 13(19), 2638; https://doi.org/10.3390/nano13192638 - 25 Sep 2023
Cited by 4 | Viewed by 1927
Abstract
Silver sulfide phases, such as body-centered cubic argentite and monoclinic acanthite, are widely known. Traditionally, acanthite is regarded as the only low-temperature phase of silver sulfide. However, the possible existence of other low-temperature phases of silver sulfide cannot be ruled out. Until now, [...] Read more.
Silver sulfide phases, such as body-centered cubic argentite and monoclinic acanthite, are widely known. Traditionally, acanthite is regarded as the only low-temperature phase of silver sulfide. However, the possible existence of other low-temperature phases of silver sulfide cannot be ruled out. Until now, there have been only a few suggestions about low-temperature Ag2S phases that differ from monoclinic acanthite. The lack of a uniform approach has hampered the prediction of such phases. In this work, the use of such an effective tool as an evolutionary algorithm for the first time made it possible to perform a broad search for the model Ag2S phases of silver sulfide, which are low-temperature with respect to cubic argentite. The possibility of forming Ag2S phases with cubic, tetragonal, orthorhombic, trigonal, monoclinic, and triclinic symmetry is considered. The calculation of the cohesion energy and the formation enthalpy show, for the first time, that the formation of low-symmetry Ag2S phases is energetically most favorable. The elastic stiffness constants cij of all predicted Ag2S phases are computed, and their mechanical stability is determined. The densities of the electronic states of the predicted Ag2S phases are calculated. The prediction of low-temperature Ag2S structures indicates the possibility of synthesizing new silver sulfide phases with improved properties. Full article
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18 pages, 6167 KiB  
Article
Analyzing Acceptor-like State Distribution of Solution-Processed Indium-Zinc-Oxide Semiconductor Depending on the In Concentration
by Dongwook Kim, Hyeonju Lee, Youngjun Yun, Jaehoon Park, Xue Zhang, Jin-Hyuk Bae and Sungkeun Baang
Nanomaterials 2023, 13(15), 2165; https://doi.org/10.3390/nano13152165 - 26 Jul 2023
Cited by 3 | Viewed by 1551
Abstract
Understanding the density of state (DOS) distribution in solution-processed indium-zinc-oxide (IZO) thin-film transistors (TFTs) is crucial for addressing electrical instability. This paper presents quantitative calculations of the acceptor-like state distribution of solution-processed IZO TFTs using thermal energy analysis. To extract the acceptor-like state [...] Read more.
Understanding the density of state (DOS) distribution in solution-processed indium-zinc-oxide (IZO) thin-film transistors (TFTs) is crucial for addressing electrical instability. This paper presents quantitative calculations of the acceptor-like state distribution of solution-processed IZO TFTs using thermal energy analysis. To extract the acceptor-like state distribution, the electrical characteristics of IZO TFTs with various In molarity ratios were analyzed with respect to temperature. An Arrhenius plot was used to determine electrical parameters such as the activation energy, flat band energy, and flat band voltage. Two calculation methods, the simplified charge approximation and the Meyer–Neldel (MN) rule-based carrier–surface potential field-effect analysis, were proposed to estimate the acceptor-like state distribution. The simplified charge approximation established the modeling of acceptor-like states using the charge–voltage relationship. The MN rule-based field-effect analysis validated the DOS distribution through the carrier–surface potential relationship. In addition, this study introduces practical and effective approaches for determining the DOS distribution of solution-processed IZO semiconductors based on the In molarity ratio. The profiles of the acceptor-like state distribution provide insights into the electrical behavior depending on the doping concentration of the solution-processed IZO semiconductors. Full article
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17 pages, 6076 KiB  
Article
Numerical Investigation on the Effect of Electrical Parameters on the Discharge Characteristics of NS-SDBD
by Sijia Liang, Yang Yu, Borui Zheng and Yuepeng Mao
Coatings 2023, 13(7), 1237; https://doi.org/10.3390/coatings13071237 - 11 Jul 2023
Cited by 1 | Viewed by 1326
Abstract
There are numerous scientific and engineering fields where the surface dielectric barrier discharge driven by nanosecond pulses (NS-SDBD) has important applications. To improve its performance, more research is still needed on the effects of electrical parameters on the NS-SDBD actuator’s discharge characteristics. In [...] Read more.
There are numerous scientific and engineering fields where the surface dielectric barrier discharge driven by nanosecond pulses (NS-SDBD) has important applications. To improve its performance, more research is still needed on the effects of electrical parameters on the NS-SDBD actuator’s discharge characteristics. In this study, a two-dimensional numerical model based on 13 discharge particle chemical processes was constructed using a numerical simulation approach, producing findings for the NS-SDBD actuator’s voltage–current (V-A) characteristics, discharge profile, and spectrum analysis. Additionally, a comprehensive investigation into the trends and underlying mechanisms of the effects of the voltage amplitude, pulse width, rise time, and fall time parameters on the discharge behavior of the NS-SDBD actuator was carried out. The results show that higher voltage amplitudes increase the maximum current and electron density, which enhances the plasma excitation effect. The peak power deposition during the second discharge is also raised by longer pulse widths and rise times, whereas the total power deposition during the second discharge is decreased by longer fall times. Full article
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10 pages, 9901 KiB  
Communication
Identifying and Modeling Resonance-Related Fluctuations on the Experimental Characteristic Impedance for PCB and On-Chip Transmission Lines
by Yojanes Rodríguez-Velásquez, Reydezel Torres-Torres and Roberto Murphy-Arteaga
Electronics 2023, 12(13), 2994; https://doi.org/10.3390/electronics12132994 - 7 Jul 2023
Cited by 1 | Viewed by 1487
Abstract
It is well known that the fluctuations in experimentally obtained characteristic impedance versus frequency curves are associated with resonances originated by standing waves bouncing back and forth between the transitions at the transmission line terminations. In fact, microwave engineers are aware of the [...] Read more.
It is well known that the fluctuations in experimentally obtained characteristic impedance versus frequency curves are associated with resonances originated by standing waves bouncing back and forth between the transitions at the transmission line terminations. In fact, microwave engineers are aware of the difficulty to completely remove the parasitic effect of these transitions, which makes obtaining smooth and physically expected frequency-dependent curves for the characteristic impedance a tough task. Here, we point out for the first time that these curves exhibit additional fluctuations within the microwave range due to standing waves taking place within the transition itself. Experimental verification of this fact was carried out by extracting this fundamental parameter from measurements performed on on-chip and printed circuit board (PCB) lines using probe pad adapters and coaxial connectors. We demonstrate that the lumped circuit approach to represent the transitions lacks validity when the additional fluctuations due to the connectors become apparent, and we propose a new model including transmission line effects within the transition. Full article
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14 pages, 3055 KiB  
Article
Investigating the Electromechanical Properties of Carbon Black-Based Conductive Polymer Composites via Stochastic Modeling
by Tyler Albright and Jared Hobeck
Nanomaterials 2023, 13(10), 1641; https://doi.org/10.3390/nano13101641 - 14 May 2023
Cited by 1 | Viewed by 1526
Abstract
Conductive polymer composites (CPCs) have shown potential for structural health monitoring applications based on repeated findings of irreversible transducer electromechanical property change due to fatigue. In this research, a high-fidelity stochastic modeling framework is explored for predicting the electromechanical properties of spherical element-based [...] Read more.
Conductive polymer composites (CPCs) have shown potential for structural health monitoring applications based on repeated findings of irreversible transducer electromechanical property change due to fatigue. In this research, a high-fidelity stochastic modeling framework is explored for predicting the electromechanical properties of spherical element-based CPC materials at bulk scales. CPC dogbone specimens are manufactured via casting and their electromechanical properties are characterized via uniaxial tensile testing. Model parameter tuning, demonstrated in previous works, is deployed for improved simulation fidelity. Modeled predictions are found in agreement with experimental results and compared to predictions from a popular analytical model in the literature. Full article
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14 pages, 4801 KiB  
Article
Characteristics of Offset Corbino Thin Film Transistor: A Physical Model
by Jiaquan Kong, Chuan Liu, Xiaojie Li, Hai Ou, Juncong She, Shaozhi Deng and Jun Chen
Electronics 2023, 12(10), 2195; https://doi.org/10.3390/electronics12102195 - 11 May 2023
Cited by 4 | Viewed by 1757
Abstract
Offset Corbino thin film transistor is a good candidate for high voltage thin film transistor (HVTFT) due to the uniform drain electric field distribution benefiting from the circular structure. The physical model of offset Corbino thin film transistor characteristics has yet to be [...] Read more.
Offset Corbino thin film transistor is a good candidate for high voltage thin film transistor (HVTFT) due to the uniform drain electric field distribution benefiting from the circular structure. The physical model of offset Corbino thin film transistor characteristics has yet to be clarified. In this study, Equations are derived to describe the current–voltage relations of Corbino TFT with offset at the drain or source sides. The influence of offset position and parameters on the saturation voltage and the saturation current was described quantitatively. Three-dimensional Computer-Aided Design simulation and experiment results verify the theoretical physical model. Our physical model provides design rules for high voltage offset Corbino TFT when considering the voltage tolerance and saturation current balance. Full article
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