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Polarization mechanism of classic ferroelectric materials. (a) A unit cell of perovskite, where metal atoms A and B are in the center of oxygen octahedrons relatively. The states of unpolarization (or fresh state), upward polarization, and downward polarization are shown, respectively. (b) A molecular chain of PVDF, where C atoms, F atoms, and H atoms are labeled with different colors. The states of unpolarization (or fresh state), upward polarization, and downward polarization are shown, respectively. (c) A typical ferroelectric hysteresis loop, where P s is saturated polarization, P r is remnant polarization, and E c is the coercive field.
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![FIG. 4. Nonvolatile memories based on FeFETs. [(a)-(c)] Schematic and...](publication/368766173/figure/fig4/AS:11431281122200360@1677244703167/Nonvolatile-memories-based-on-FeFETs-a-c-Schematic-and-performance-of-a-FeFET_Q320.jpg)
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Ferroelectric materials have shown great value in the modern semiconductor industry and are considered important function materials due to their high dielectric constant and tunable spontaneous polarization. A ferroelectric field effect transistor (FeFET) is a field effect transistor (FET) with ferroelectric polarization field introduced to regulat...
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... originates from the special crystal structure of ferroelectrics. Taking perovskite ABO 3 as an example, 67,92 as shown in Fig. 2(a), the cubic phase is a symmetrical paraelectric phase without spontaneous polarization, where metal atoms A and B are located in the center of oxygen octahedrons, respectively. The asymmetric ferroelectric phases of perovskites include the tetragonal phase, orthogonal phase, and triangular phase. In ferroelectric phases, positive and ...
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... strongest polarity is the b phase, which originates from the non-polar a phase. A molecular chain of the a phase is stretched to several times its original length to attain the highly oriented b phase. The direction of ferroelectric polarization is perpendicular to the direction of stretching. A symmetrical phase without polarization is shown in Fig. 2(b), with F atoms and H atoms distributed equally at both sides of the chain. When P(VDF-TrFE) exhibits upward polarization, most of the F atoms move to the upward side of the chain. Under ideal conditions, all F atoms of P(VDF-TrFE) are located at one side of the chain while all H atoms are located at the other side, i.e., exhibiting ...
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... reach a maximum value. Similarly, when P(VDF-TrFE) exhibits downward polarization, the F atoms move to the downward side of the chain. In the initial state, the orientation of the electric dipole moment in ferroelectric is random, and ferroelectric appears electrical neutrality externally, corresponding to point O in P À E hysteresis loop in Fig. 2(c). When an external electric field is applied, the orientation of the electric dipole moment tends to be in line with the direction of the external field, and the ferroelectric polarization field generates inside. As shown in Fig. 2(a), the change of electric dipole moment orientation is achieved by the relative displacement of positive ...
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... and ferroelectric appears electrical neutrality externally, corresponding to point O in P À E hysteresis loop in Fig. 2(c). When an external electric field is applied, the orientation of the electric dipole moment tends to be in line with the direction of the external field, and the ferroelectric polarization field generates inside. As shown in Fig. 2(a), the change of electric dipole moment orientation is achieved by the relative displacement of positive and negative ions. Taking an oxygen octahedron as a baseline, the positive ion inside moves along the symmetry axis. When the applied electric field causes the positive ion to move downward in the oxygen octahedron, the direction of ...
Citations
... Ferroelectricity was first discovered in Rochelle salts 15 , however, the unstable and water-soluble nature has greatly limited their applications and research. During World War II, the discovery of the ferroelectricity of the chalcogenide material barium titanate (BTO) gave a great impetus to the development of ferroelectric materials for extreme applications, followed by the emergence of many different materials and structures 16 . The characteristic of ferroelectric materials is that spontaneous polarization can be generated within a certain temperature range and the polarization properties are regulated by an external electric field. ...
After more than a hundred years of development, ferroelectric materials have demonstrated their strong potential to people, and more and more ferroelectric materials are being used in the research of ferroelectric transistors (FeFETs). As a new generation of neuromorphic devices, ferroelectric materials have attracted people's attention due to their powerful functions and many characteristics. This article summarizes the development of ferroelectric material systems in recent years and discusses the simulation of artificial synapses. The mainstream ferroelectric materials are divided into traditional perovskite structure, fluorite structure, organic polymer, and new 2D van der Waals ferroelectricity. The principles, research progress, and optimization for brain like computers of each material system are introduced, and the latest application progress is summarized. Finally, the scope of application of different material systems is discussed, with the aim of helping people screen out different material systems based on different needs.
... The ferroelectric field-effect transistor (Fe-FET) is an a ractable alternative component for the artificial intelligence (AI) chip, due to the parallel function of data computing and non-volatile storage, the fast read and write speed, and the low power consumption [1,2]. For high integration in advanced semiconductor processing, the nanoscale ferroelectric compound and composite have been intensively studied. ...
There is much interest regarding the “coupled ferroelectricity and superconductivity” in the two-dimensional material, bilayer Td-MoTe2; however, the value and the type of electric polarization are unknown. The device structure and the measurement method show that the measured material is the composite of the pseudo-bilayer quantum Hall system, with a thickness of about thirty-six nanometers. The derived dielectric hysteresis loops and the calculated electronic structure reveal that the condensed large polarons are responsible for the reverse ferroelectricity and the coupled superconductivity. The maximum value of polaron-type electric polarization is ~12 nC/μm² or 1.2 × 10⁴ μc/cm².
... In ferroelectric, the shape of the hysteresis curve is determined according to the remanent polarization Pr and the coercive field Ec, which has a great influence on characteristics such as SS [26][27]. In addition, since remanent polarization Pr and coercive field Ec affect the current-voltage characteristics of FET using ferroelectric, they will eventually affect DIBL. ...
This study presents an analytical model for the drain-induced barrier lowering (DIBL) of a junctionless gate-all-around FET with ferroelectric, utilizing a 2D potential model. A multilayer structure of metal-ferroelectric-metal-insulator-semiconductor is used as the gate, as well as the remanent polarization and coercive field values corresponding to HZO are used. The DIBLs obtained with the proposed model demonstrate good agreement with those obtained using the second derivative method, which relies on the 2D relationship between drain current and gate voltage. The results demonstrate that an increase in ferroelectric thickness leads to a negative DIBL value due to the ferroelectric charge. Additionally, there exists an inverse relationship between ferroelectric thickness and channel length to achieve a DIBL value of 0. This condition is satisfied only with the increase of the ferroelectric thickness as the channel radius and insulator thickness increase. The DIBLs increase with higher remanent polarization and lower coercive field, remaining constant when the ratio of remanent polarization and coercive field is maintained.
... This integration aims to optimize the multi-gas sensor's structure, enhance its performance, and improve power efficiency. Additionally, considering that the gas-induced gate work function modulation can be perceived as an integral aspect of the gate voltage (i.e., effective gate voltage), exploiting the negative capacitance of ferroelectric nanomaterials [73][74][75][76][77][78][79] emerges as a promising strategy. This strategy has the potential to amplify the impact of gas-induced changes in gate work function on the device electrostatics and characteristics. ...
In this paper, a new junctionless graphene nanoribbon tunnel field-effect transistor (JLGNR TFET) is proposed as a multi-gas nanosensor. The nanosensor has been computationally assessed using a quantum simulation based on the self-consistent solutions of the mode space non-equilibrium Green’s function (NEGF) formalism coupled with the Poisson’s equation considering ballistic transport conditions. The proposed multi-gas nanosensor is endowed with two top gates ensuring both reservoirs’ doping and multi-gas sensing. The investigations have included the IDS-VGS transfer characteristics, the gas-induced electrostatic modulations, subthreshold swing, and sensitivity. The order of change in drain current has been considered as a sensitivity metric. The underlying physics of the proposed JLGNR TFET-based multi-gas nanosensor has also been studied through the analysis of the band diagrams behavior and the energy-position-resolved current spectrum. It has been found that the gas-induced work function modulation of the source (drain) gate affects the n-type (p-type) conduction branch by modulating the band-to-band tunneling (BTBT) while the p-type (n-type) conduction branch still unaffected forming a kind of high selectivity from operating regime point of view. The high sensitivity has been recorded in subthermionic subthreshold swing (SS < 60 mV/dec) regime considering small gas-induced gate work function modulation. In addition, advanced simulations have been performed for the detection of two different types of gases separately and simultaneously, where high-performance has been recorded in terms of sensitivity, selectivity, and electrical behavior. The proposed detection approach, which is viable, innovative, simple, and efficient, can be applied using other types of junctionless tunneling field-effect transistors with emerging channel nanomaterials such as the transition metal dichalcogenides materials. The proposed JLGNRTFET-based multi-gas nanosensor is not limited to two specific gases but can also detect other gases by employing appropriate gate materials in terms of selectivity.
... Infrared focal plane arrays (IRFPAs) have the advantages of high sensitivity, good environmental adaptability, and strong anti-interference. They are widely used by the military and civilians as defense weapons and for infrared remote sensing and the meteorological environment [1][2][3][4][5][6][7][8][9]. The small element IRFPAs have always been a research hotspot at both home and abroad [10][11][12][13]. ...
The crosstalk of the small detection photosensitive elements test has always been the difficulty of research on infrared focal plane arrays (IRFPAs). With the decrease in the element size in the IRFPAs, the crosstalk of small detection photosensitive elements cannot be tested by the existing small spot method. In this paper, a novel eye hole method to realize the crosstalk of the small element IRFPAs test is proposed. The novel eye hole method is to make eye holes on the substrate. The transmittance of the eye holes in the substrate is 100%, while the transmittance of the other component in the substrate is 0. The substrate with the eye holes is fixed in front of small element IRFPAs to achieve the crosstalk of the small elements test. The filters selected by 9 elements and 25 elements as the eye hole unit are designed and prepared. The experimental results show that 25 elements are selected as the eye hole unit for the IRFPAs with the element size of 25 μm × 25 μm. The eye holes are formed tightly and repeatedly arranged. The crosstalk of the InSb IRFPAs with the element size of 25 μm × 25 μm by the novel eye hole method is 3.86%. The results are of great reference significance for improving the test level of small element IRFPA.
... One way to achieve the self-powered photoresponse is to construct heterojunctions, [18][19][20][21] which lead to the rapid separation of the photogenerated electron-hole pairs by the built-in electric field at the heterojunction interface. [19][20][21][22][23][24] To realize broadband detection, one feasible way is to find narrow bandgap materials, [25][26][27][28] which have the ability to absorb light with a wide spectrum. AgIn 5 Se 8 (AIS), an n-type ternary semiconductor, [29] has a direct bandgap of 1.25 eV, [30] which enables photons to be excited from the valence band to the conduction band without the assistance of phonons. ...
Type II p-n heterojunction could improve the photodetecting performance of a photodetector due to the excellent ability of carrier separation. N-type AgIn 5 Se 8 (AIS) exhibits a large optical absorption coefficient, high optical conductivity and suitable bandgap, which shows potential application in broadband photodetecting. Even though our previous study on AgIn 5 Se 8 /FePSe 3 exhibited a good response speed, it still gave low responsivity due to the poor quality of p-type FePSe 3 thin-film. Se with a direct bandgap (around 1.7 eV), p-type conductivity, high electron mobility and high carrier density is likely to form a low dimensional structure, which leads to the increase of effective contact area of the heterojunction and further improves the photodetector performance. In this work, continuous and dense t-Se thin-film was prepared by electrochemical deposition. The self-powered AgIn 5 Se 8 /t-Se heterojunction photodetector exhibited a broadband detecting range from 365 to 1200 nm. The responsivity and detectivity of the heterojunction photodetector are 32 mA/W and 1.8×10 ⁹ Jones, respectively, which show around 9 and 4 times higher than the AgIn 5 Se 8 /FePSe 3 heterojunction photodetector. The main reason is due to the good quality of the t-Se thin-film and the formation of the low dimensional t-Se nanoribbons, which optimized the transport pathway of carriers. The results indicate that AgIn 5 Se 8 /t-Se heterojunction proves to be an excellent candidate for broadband and self-powered photoelectronic devices.
Two-dimensional van der Waals ferroelectric materials play an important role in a wide spectrum of semiconductor technologies and device applications. Integration of ferroelectrics into 2D-layered material-based devices is expected to offer intriguing working principles and add desired functionalities for next-generation electronics. Here, we investigate the electric and thermoelectric properties of thin layers of the 2H and 3R polymorphs of α-In2Se3 embedded in solid-state three-terminal devices. Charge transport measurements reveal a hysteretic behavior that can be ascribed to the effect of ferroelectric polarization at the metal electrode/2D semiconductor interfaces. The thermoelectric investigation of the same devices unveils a well-defined negative signal of the order of 100–200 μV/K in absolute value for the 2H polymorph, showing a slight modulation as a function of the gate voltage. An analogous but noisy thermoelectric voltage is measured for devices based on the 3R polymorph, where indeed a constant finite transversal offset in the 100 μV-few mV range is detected, which does not depend on the applied temperature gradient. We argue that these experimental observations are related to a strong residual in-plane ferroelectric polarization in the 3R α-In2Se3 polymorph thin layer. Our results show that the thermoelectric response is a fine probe of the ferroelectric character of 2D layered α-In2Se3.
Future pulsed‐power electronic systems based on dielectric capacitors require the use of environment‐friendly materials with high energy‐storage performance that can operate efficiently and reliably in harsh environments. Here, a study of multilayer structures, combining paraelectric‐like Ba0.6Sr0.4TiO3 (BST) with relaxor‐ferroelectric BaZr0.4Ti0.6O3 (BZT) layers on SrTiO3‐buffered Si substrates, with the goal to optimize the high energy‐storage performance is presented. The energy‐storage properties of various stackings are investigated and an extremely large maximum recoverable energy storage density of ≈165.6 J cm⁻³ (energy efficiency ≈ 93%) is achieved for unipolar charging–discharging of a 25‐nm‐BZT/20‐nm‐BST/910‐nm‐BZT/20‐nm‐BST/25‐nm‐BZT multilayer structure, due to the extremely large breakdown field of 7.5 MV cm⁻¹ and the lack of polarization saturation at high fields in this device. Strong indications are found that the breakdown field of the devices is determined by the outer layers of the multilayer stack and can be increased by improving the quality of these layers. Authors are also able to deduce design optimization rules for this material combination, which can be to a large extend justify by structural analysis. These rules are expected also to be useful for optimizing other multilayer systems and are therefore very relevant for further increasing the energy storage density of capacitors.
