Ambipolar transistors from low-dimensional semiconductors with high charge-transporting capability and tunable bandgap have developed rapidly in functional applications, such as neuromorphic computing, lighting, storing, and sensing. However, there are still challenges to balance procedure complexity and device performance, such as current on–off ratio, work voltage, and operational reliability. Here, we demonstrated solution-processed ambipolar ionic-gated transistors (amIGTs) from stacked heterojunctions of 1D/2D SnO2/Se composites and 2D WSe2 nanosheets, with high current on–off ratios, low work voltage, and high operational stability. The 1D/2D SnO2/Se composite, involving 1D SeNWs and 2D SnO2 nanosheets, was directly obtained by a one-step self-conversion from 2D SnSe nanosheets. We found that charge transports in SnO2/Se were greatly improved by formed efficient channels of 1D SeNWs, giving the extremely low value of subthreshold swing (SS) of reaches as low as 68 mV/dec, very close to the limitation (60 mV/dec) of “Boltzmann theory.” Using the amIGTs, we achieved highly stable and operation-tunable thermal sensing, with a high sensitivity of 16%/K, high resolution of 0.1 K, and a large linear detection range of 100 K. Our results hold great implications for wide applications of the low-dimensional material-based transistors in the post-Moore era.
{"title":"Solution-processed ambipolar ionic-gated transistors from 1D/2D heterojunctions of WSe2 and self-conversed SnO2/Se enabling high-sensitivity thermal sensing","authors":"Jiehua Zhang, Feng Li, Wenwen Chen, Baobao Xu, Yiyi Yang, Zhixin Xie, Haihua Xu","doi":"10.1063/5.0228989","DOIUrl":"https://doi.org/10.1063/5.0228989","url":null,"abstract":"Ambipolar transistors from low-dimensional semiconductors with high charge-transporting capability and tunable bandgap have developed rapidly in functional applications, such as neuromorphic computing, lighting, storing, and sensing. However, there are still challenges to balance procedure complexity and device performance, such as current on–off ratio, work voltage, and operational reliability. Here, we demonstrated solution-processed ambipolar ionic-gated transistors (amIGTs) from stacked heterojunctions of 1D/2D SnO2/Se composites and 2D WSe2 nanosheets, with high current on–off ratios, low work voltage, and high operational stability. The 1D/2D SnO2/Se composite, involving 1D SeNWs and 2D SnO2 nanosheets, was directly obtained by a one-step self-conversion from 2D SnSe nanosheets. We found that charge transports in SnO2/Se were greatly improved by formed efficient channels of 1D SeNWs, giving the extremely low value of subthreshold swing (SS) of reaches as low as 68 mV/dec, very close to the limitation (60 mV/dec) of “Boltzmann theory.” Using the amIGTs, we achieved highly stable and operation-tunable thermal sensing, with a high sensitivity of 16%/K, high resolution of 0.1 K, and a large linear detection range of 100 K. Our results hold great implications for wide applications of the low-dimensional material-based transistors in the post-Moore era.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"12 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142696877","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This perspective article presents the density functional theory and traces its evolution. With the advancement in density functional theory-based computations and the efforts to collate the data generated through density functional theory, the field now has a good repository/database of materials and their properties. This repository, though not as substantial as generally used for machine learning, has nonetheless made it possible to combine density functional theory and machine learning. This article highlights current research challenges and presents an optimistic outlook for the future of “Density Functional Theory with Machine Learning” by discussing some specific examples.
{"title":"Density functional theory and material databases in the era of machine learning","authors":"Arti Kashyap","doi":"10.1063/5.0235654","DOIUrl":"https://doi.org/10.1063/5.0235654","url":null,"abstract":"This perspective article presents the density functional theory and traces its evolution. With the advancement in density functional theory-based computations and the efforts to collate the data generated through density functional theory, the field now has a good repository/database of materials and their properties. This repository, though not as substantial as generally used for machine learning, has nonetheless made it possible to combine density functional theory and machine learning. This article highlights current research challenges and presents an optimistic outlook for the future of “Density Functional Theory with Machine Learning” by discussing some specific examples.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"7 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142713255","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tunnel magnetoresistance (TMR) ratio is a key parameter characterizing the performance of a magnetic tunnel junction (MTJ), and a large TMR ratio is essential for the practical application of it. Generally, the traditional solutions to increasing the TMR ratio are to choose different material combinations as the ferromagnetic (FM) leads and nonmagnetic tunnel barrier. In this work, we study an architecture of MTJs of “FM/barrier/FM/barrier/FM” with double barriers, in contrast to the traditional single barrier structure “FM/barrier/FM.” We first analytically show that double barrier MTJ will generally have much higher TMR ratio than the single barrier MTJ and then substantiate it with the well-known example of “Fe/MgO/Fe” MTJ. Based on density functional calculations combined with nonequilibrium Green's function technique for quantum transport study, in the single barrier “Fe/MgO/Fe” MTJ, the TMR ratio is obtained as 122%, while in the double barrier “Fe/MgO/Fe/MgO/Fe” MTJ, it is greatly increased to 802%, suggesting that double barrier design can greatly enhance the TMR and can be taken into consideration in the design of MTJs.
{"title":"Double-barrier magnetic tunnel junctions with enhanced tunnel magnetoresistance","authors":"Xiaohong Zheng, Shili Yang, Zhifan Zheng, Chun-Sheng Liu, Weiyang Wang, Lei Zhang","doi":"10.1063/5.0235559","DOIUrl":"https://doi.org/10.1063/5.0235559","url":null,"abstract":"Tunnel magnetoresistance (TMR) ratio is a key parameter characterizing the performance of a magnetic tunnel junction (MTJ), and a large TMR ratio is essential for the practical application of it. Generally, the traditional solutions to increasing the TMR ratio are to choose different material combinations as the ferromagnetic (FM) leads and nonmagnetic tunnel barrier. In this work, we study an architecture of MTJs of “FM/barrier/FM/barrier/FM” with double barriers, in contrast to the traditional single barrier structure “FM/barrier/FM.” We first analytically show that double barrier MTJ will generally have much higher TMR ratio than the single barrier MTJ and then substantiate it with the well-known example of “Fe/MgO/Fe” MTJ. Based on density functional calculations combined with nonequilibrium Green's function technique for quantum transport study, in the single barrier “Fe/MgO/Fe” MTJ, the TMR ratio is obtained as 122%, while in the double barrier “Fe/MgO/Fe/MgO/Fe” MTJ, it is greatly increased to 802%, suggesting that double barrier design can greatly enhance the TMR and can be taken into consideration in the design of MTJs.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"3 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142713257","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Balthazar Temu, Zhao Yan, Bogdan-Petrin Ratiu, Sang Soon Oh, Qiang Li
In this work we demonstrate room temperature lasing from core-shell nanowires consisting of a radial InGaAs quantum well as the active material. The nanowires with the GaAs/InGaAs/InGaP quantum well structures are arranged in a deformed honeycomb lattice, forming a photonic crystal surface emitting laser (PCSEL). We demonstrate lasing from devices with three different nanowire diameters from undeformed, stretched, and compressed honeycomb lattices. Under optical pumping we show that the PCSEL lases at the wavelength of 966 nm (stretched pattern), with the lasing threshold of 103 μJ/cm2. The lasing wavelength increases as the nanowire diameter increases. Combining photoluminescence results and numerical simulations on the field profile and the quality factors of the devices, we establish that the lasing of the device is from the radial quantum well structure.
{"title":"Room temperature lasing from InGaAs quantum well nanowires on silicon-on-insulator substrates","authors":"Balthazar Temu, Zhao Yan, Bogdan-Petrin Ratiu, Sang Soon Oh, Qiang Li","doi":"10.1063/5.0237589","DOIUrl":"https://doi.org/10.1063/5.0237589","url":null,"abstract":"In this work we demonstrate room temperature lasing from core-shell nanowires consisting of a radial InGaAs quantum well as the active material. The nanowires with the GaAs/InGaAs/InGaP quantum well structures are arranged in a deformed honeycomb lattice, forming a photonic crystal surface emitting laser (PCSEL). We demonstrate lasing from devices with three different nanowire diameters from undeformed, stretched, and compressed honeycomb lattices. Under optical pumping we show that the PCSEL lases at the wavelength of 966 nm (stretched pattern), with the lasing threshold of 103 μJ/cm2. The lasing wavelength increases as the nanowire diameter increases. Combining photoluminescence results and numerical simulations on the field profile and the quality factors of the devices, we establish that the lasing of the device is from the radial quantum well structure.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"257 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142713267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lead sulfide (PbS) is widely recognized as a promising n-type thermoelectric material for use in the middle-temperature range. Although it already exhibits favorable electronic and thermal properties, its thermoelectric performance could be further enhanced by addressing the disparity between the light and heavy bands in the conduction band, thereby optimizing electrical transport, and by modifying the strength of its chemical bonds to reduce lattice thermal conductivity. In this study, we demonstrate that introducing just small amounts of antimony (Sb) into PbS generates a unique combination of interstitial and substitutional doping that leads to a significant improvement in both directions. Substitutional doping enhances the degeneracy between the light and heavy bands, increasing carrier mobility. At the same time, interstitial doping introduces a new resonance state near the Fermi level, providing an additional channel for electron transport while boosting carrier concentration. These synergistic effects lead to a marked increase in the power factor of PbS, achieving an average power factor (PFavg) of 1.07 mW m−1 K−2 across the temperature range of 320–873 K. Moreover, Sb substitution for Pb induces a shift in the surrounding S atoms toward Sb, weakening their bonds with neighboring Pb atoms. This shift results in a coexistence of strong and weak chemical bonds, which effectively reduces lattice thermal conductivity. Additionally, the defect structures introduced by Sb doping effectively scatter phonons, further lowering lattice thermal conductivity. As a result, PbS doped with 0.5% Sb exhibits a figure of merit (ZT) of 0.73 at 873 K, which is approximately three times higher than that of undoped PbS.
{"title":"Synergistic effects of interstitial and substitutional doping on the thermoelectric properties of PbS","authors":"Benteng Wu, Xueke Zhao, Mochen Jia, Dawei Yang, Yu Liu, Hongzhang Song, Dongyang Wang, Andreu Cabot, Mengyao Li","doi":"10.1063/5.0238037","DOIUrl":"https://doi.org/10.1063/5.0238037","url":null,"abstract":"Lead sulfide (PbS) is widely recognized as a promising n-type thermoelectric material for use in the middle-temperature range. Although it already exhibits favorable electronic and thermal properties, its thermoelectric performance could be further enhanced by addressing the disparity between the light and heavy bands in the conduction band, thereby optimizing electrical transport, and by modifying the strength of its chemical bonds to reduce lattice thermal conductivity. In this study, we demonstrate that introducing just small amounts of antimony (Sb) into PbS generates a unique combination of interstitial and substitutional doping that leads to a significant improvement in both directions. Substitutional doping enhances the degeneracy between the light and heavy bands, increasing carrier mobility. At the same time, interstitial doping introduces a new resonance state near the Fermi level, providing an additional channel for electron transport while boosting carrier concentration. These synergistic effects lead to a marked increase in the power factor of PbS, achieving an average power factor (PFavg) of 1.07 mW m−1 K−2 across the temperature range of 320–873 K. Moreover, Sb substitution for Pb induces a shift in the surrounding S atoms toward Sb, weakening their bonds with neighboring Pb atoms. This shift results in a coexistence of strong and weak chemical bonds, which effectively reduces lattice thermal conductivity. Additionally, the defect structures introduced by Sb doping effectively scatter phonons, further lowering lattice thermal conductivity. As a result, PbS doped with 0.5% Sb exhibits a figure of merit (ZT) of 0.73 at 873 K, which is approximately three times higher than that of undoped PbS.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"257 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142713254","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Štaupienė, A. Zelioli, A. Špokas, A. Vaitkevičius, B. Čechavičius, S. Stanionytė, S. Raišys, R. Butkutė, E. Dudutienė
We present a detailed study on the optical properties of GaAsBi/GaAs multiple quantum well structure, optimized for the active area for vertical-external-cavity surface-emitting lasers. The quantum structure was grown by molecular beam epitaxy with every other barrier made thinner to have a homogeneous structure with high photoluminescence (PL) intensity. PL measurements were carried out in a wide temperature range from 4 to 300 K. The PL band of 1.085 eV was attributed to the optical transition in QWs with 8.0%Bi. The S-shaped temperature dependence of PL peak positions showed high localization effect of 30 meV. The internal quantum efficiency (IQE) was evaluated for the bismide structures with a modified ABB* method, which includes contribution from trap-assisted Auger recombination. The calculations showed low IQE of <0.025% for GaAs0.92Bi0.08/GaAs 12 QWs structure, which was explained by the low growth temperature, resulting in a high density of point defects in the material.
我们对 GaAsBi/GaAs 多量子阱结构的光学特性进行了详细研究，该结构针对垂直外腔表面发射激光器的有源区进行了优化。该量子结构是通过分子束外延法生长的，每隔一个势垒都做得更薄，以获得具有高光致发光（PL）强度的均匀结构。在 4 至 300 K 的宽温度范围内进行了光致发光测量。铋含量为 8.0% 的 QW 中的光学转变产生了 1.085 eV 的光致发光带。PL 峰位置的 S 型温度依赖性显示出 30 meV 的高局域化效应。利用改进的 ABB* 方法评估了双晶结构的内部量子效率 (IQE)，其中包括陷阱辅助奥杰尔重组的贡献。计算结果表明，GaAs0.92Bi0.08/GaAs 12 QWs 结构的 IQE 较低，仅为 <0.025%，原因是生长温度较低，导致材料中的点缺陷密度较高。
{"title":"Internal quantum efficiency of GaAsBi MQW structure for the active region of VECSELs","authors":"A. Štaupienė, A. Zelioli, A. Špokas, A. Vaitkevičius, B. Čechavičius, S. Stanionytė, S. Raišys, R. Butkutė, E. Dudutienė","doi":"10.1063/5.0234853","DOIUrl":"https://doi.org/10.1063/5.0234853","url":null,"abstract":"We present a detailed study on the optical properties of GaAsBi/GaAs multiple quantum well structure, optimized for the active area for vertical-external-cavity surface-emitting lasers. The quantum structure was grown by molecular beam epitaxy with every other barrier made thinner to have a homogeneous structure with high photoluminescence (PL) intensity. PL measurements were carried out in a wide temperature range from 4 to 300 K. The PL band of 1.085 eV was attributed to the optical transition in QWs with 8.0%Bi. The S-shaped temperature dependence of PL peak positions showed high localization effect of 30 meV. The internal quantum efficiency (IQE) was evaluated for the bismide structures with a modified ABB* method, which includes contribution from trap-assisted Auger recombination. The calculations showed low IQE of &lt;0.025% for GaAs0.92Bi0.08/GaAs 12 QWs structure, which was explained by the low growth temperature, resulting in a high density of point defects in the material.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"80 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142713259","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Al Shukaili, I. Berrai, F. Al Ma'Mari, M. Ramu, S. Bhatti, M. T. Zar Myint, S. Al Harthi, S. M. Cherif, S. N. Piramanayagam, R. Sbiaa
Asymmetric (Pt/Co/X) multilayers where X is Ta or W have been investigated. Both structures showed a tailed hysteresis loop indicating the existence of skyrmions. The interfacial Dzyaloshinskii–Moriya interaction (iDMI) extracted from Brillouin light scattering revealed that sample with W has a value of −0.52 mJ/m2, which is ∼2.5 times larger than Ta case. In addition to iDMI, the perpendicular magnetic anisotropy is also stronger for W case due to the orbital hybridization at the interface. From magnetic force microscopy, W sample showed a change from unusual rod-like domains to skyrmions, while the change was from labyrinth domains to skyrmions in Ta-based structure.
研究了 X 为 Ta 或 W 的不对称（Pt/Co/X）多层膜。这两种结构都出现了尾状滞后环，表明存在天离子。从布里渊光散射中提取的界面 Dzyaloshinskii-Moriya 相互作用（iDMI）显示，W 样品的值为 -0.52 mJ/m2，是 Ta 样品的 2.5 倍。除了 iDMI 外，由于界面上的轨道杂化，W 样品的垂直磁各向异性也更强。从磁力显微镜观察，W 样品显示了从不规则的棒状结构域到天线状结构域的变化，而 Ta 基结构则是从迷宫状结构域到天线状结构域的变化。
{"title":"Magnetic textures and perpendicular anisotropy in asymmetric multilayers with Ta and W","authors":"S. Al Shukaili, I. Berrai, F. Al Ma'Mari, M. Ramu, S. Bhatti, M. T. Zar Myint, S. Al Harthi, S. M. Cherif, S. N. Piramanayagam, R. Sbiaa","doi":"10.1063/5.0239692","DOIUrl":"https://doi.org/10.1063/5.0239692","url":null,"abstract":"Asymmetric (Pt/Co/X) multilayers where X is Ta or W have been investigated. Both structures showed a tailed hysteresis loop indicating the existence of skyrmions. The interfacial Dzyaloshinskii–Moriya interaction (iDMI) extracted from Brillouin light scattering revealed that sample with W has a value of −0.52 mJ/m2, which is ∼2.5 times larger than Ta case. In addition to iDMI, the perpendicular magnetic anisotropy is also stronger for W case due to the orbital hybridization at the interface. From magnetic force microscopy, W sample showed a change from unusual rod-like domains to skyrmions, while the change was from labyrinth domains to skyrmions in Ta-based structure.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"3 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142713256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Luca Berchialla, Gavin M. Macauley, Laura J. Heyderman
Artificial spin ices are arrays of coupled single domain nanomagnets that have mainly been explored in two dimensions. They display a number of intriguing phenomena arising from the collective behavior of the magnets including vertex frustration, emergent magnetic monopoles, and phase transitions. Escaping this flat paradigm into the third dimension is now possible, thanks to advances in fabrication and characterization of three-dimensional mesoscopic magnetic systems, which have magnetic elements with dimensions between a few 10's and a few 100's nanometers. By exploiting the extra degrees of freedom inherent to fully three-dimensional structures, it will be possible to harness the dipolar and other interactions between magnetic elements in a way that cannot be achieved in planar systems. This will offer an unparalleled opportunity to produce three-dimensional mesoscopic magnetic structures exhibiting true spin ice physics and also, more broadly, to engineer exotic magnetic states and cooperative phenomena in a range of three-dimensional artificial spin ices that may have no direct analog in natural materials. In this perspective, we review the development of research into three-dimensional artificial spin ice, highlighting the main routes by which such structures can be created and measured. We discuss some new frontiers for the field, both in terms of realizing 3D model systems, and exciting opportunities for applications, such as sensing and computing.
{"title":"Focus on three-dimensional artificial spin ice","authors":"Luca Berchialla, Gavin M. Macauley, Laura J. Heyderman","doi":"10.1063/5.0229120","DOIUrl":"https://doi.org/10.1063/5.0229120","url":null,"abstract":"Artificial spin ices are arrays of coupled single domain nanomagnets that have mainly been explored in two dimensions. They display a number of intriguing phenomena arising from the collective behavior of the magnets including vertex frustration, emergent magnetic monopoles, and phase transitions. Escaping this flat paradigm into the third dimension is now possible, thanks to advances in fabrication and characterization of three-dimensional mesoscopic magnetic systems, which have magnetic elements with dimensions between a few 10's and a few 100's nanometers. By exploiting the extra degrees of freedom inherent to fully three-dimensional structures, it will be possible to harness the dipolar and other interactions between magnetic elements in a way that cannot be achieved in planar systems. This will offer an unparalleled opportunity to produce three-dimensional mesoscopic magnetic structures exhibiting true spin ice physics and also, more broadly, to engineer exotic magnetic states and cooperative phenomena in a range of three-dimensional artificial spin ices that may have no direct analog in natural materials. In this perspective, we review the development of research into three-dimensional artificial spin ice, highlighting the main routes by which such structures can be created and measured. We discuss some new frontiers for the field, both in terms of realizing 3D model systems, and exciting opportunities for applications, such as sensing and computing.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"24 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142713312","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mengjiao Yu, Dandan Wu, Changshun Dai, Mingsheng Long, Lei Shan, Chunchang Wang, Feng Li
Antiferroelectric–ferroelectric phase transition in antiferroelectric (AFE) materials usually triggers high-performance electrocaloric effect (ECE), as represented by PbZrO3-based AFE. As an isostructure to PbZrO3, EC research in PbHfO3-based AFE ceramics are significantly left out. In this work, temperature dependent electrocaloric performances in Pb0.97La0.02(Hf0.92Ti0.08)O3 with typical AFE features are explored, and rhombohedral ferroelectric (FER), AFE1 (A1, Pbam), and AFE2 (A2, Imma) triple phases are induced as temperature increases. This leads to dual coexisting regions with FER-to-A1 and A1-to-A2 at a temperature of ∼20 °C and ∼100 °C, respectively, where local EC maxima are produced with an ΔT ∼0.06 K and ΔT ∼0.16 K (E = 70 kV/cm). These are certified by comprehensive characterizations of in situ x-ray diffractometer, AFE electrical properties, and Raman spectra analysis. This strongly indicates that AFE (Pbam)-to-AFE (Imma) phase transition could efficiently optimize ECE in PbHfO3-based AFE, in addition to the conventional understandings of FE–paraelectric and AFE–paraelectric modulation strategy. This work not only presents the potential of PbHfO3-based AFE in solid-state cooling applications but also serves as a catalyst for further seeking for high-EC AFE materials.
{"title":"Temperature dependent electrocaloric performances in Pb0.97La0.02(Hf0.92Ti0.08)O3 antiferroelectric ceramic with triple phase structures","authors":"Mengjiao Yu, Dandan Wu, Changshun Dai, Mingsheng Long, Lei Shan, Chunchang Wang, Feng Li","doi":"10.1063/5.0245821","DOIUrl":"https://doi.org/10.1063/5.0245821","url":null,"abstract":"Antiferroelectric–ferroelectric phase transition in antiferroelectric (AFE) materials usually triggers high-performance electrocaloric effect (ECE), as represented by PbZrO3-based AFE. As an isostructure to PbZrO3, EC research in PbHfO3-based AFE ceramics are significantly left out. In this work, temperature dependent electrocaloric performances in Pb0.97La0.02(Hf0.92Ti0.08)O3 with typical AFE features are explored, and rhombohedral ferroelectric (FER), AFE1 (A1, Pbam), and AFE2 (A2, Imma) triple phases are induced as temperature increases. This leads to dual coexisting regions with FER-to-A1 and A1-to-A2 at a temperature of ∼20 °C and ∼100 °C, respectively, where local EC maxima are produced with an ΔT ∼0.06 K and ΔT ∼0.16 K (E = 70 kV/cm). These are certified by comprehensive characterizations of in situ x-ray diffractometer, AFE electrical properties, and Raman spectra analysis. This strongly indicates that AFE (Pbam)-to-AFE (Imma) phase transition could efficiently optimize ECE in PbHfO3-based AFE, in addition to the conventional understandings of FE–paraelectric and AFE–paraelectric modulation strategy. This work not only presents the potential of PbHfO3-based AFE in solid-state cooling applications but also serves as a catalyst for further seeking for high-EC AFE materials.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"183 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142713251","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Changqing Li, Fuguo Tian, Zhongzhong Luo, Haoyang Luo, Jie Yan, Xiangdong Xu, Xiang Wan, Li Zhu, Chee Leong Tan, Zhihao Yu, Yong Xu, Huabin Sun
Organic ferroelectric field-effect transistors (Fe-OFETs) exhibit exceptional capabilities in mimicking biological neural systems and represent one of the primary options for flexible artificial synaptic devices. Ferroelectric polymers, such as poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)), given their strong ferroelectricity and facile solution processing, have emerged as the preferred choices for the ferroelectric dielectric layer of wearable devices. However, the solution processed P(VDF-TrFE) films can lead to high interface roughness, prone to cause excessive gate leakage. Meanwhile, the ferroelectric layer in neural computing and memory applications also faces a trade-off between storage time and energy for read/write operations. This study introduces a composite dielectric layer for Fe-OFETs, fabricated via a solution-based process. Different thicknesses of poly(N-vinylcarbazole) (PVK) are shown to significantly alter the ferroelectric hysteresis window and leakage current. The optimized devices exhibit synaptic plasticity with a transient current of 3.52 mA and a response time of approximately 50 ns. The Fe-OFETs with the composite dielectric were modeled and integrated into convolutional neural networks, achieving a 92.95% accuracy rate. This highlights the composite dielectric's advantage in neuromorphic computing. The introduction of PVK optimizes the interface and balances device performance of Fe-OFETs for neuromorphic computing.
{"title":"Organic ferroelectric transistors with composite dielectric for efficient neural computing","authors":"Changqing Li, Fuguo Tian, Zhongzhong Luo, Haoyang Luo, Jie Yan, Xiangdong Xu, Xiang Wan, Li Zhu, Chee Leong Tan, Zhihao Yu, Yong Xu, Huabin Sun","doi":"10.1063/5.0238638","DOIUrl":"https://doi.org/10.1063/5.0238638","url":null,"abstract":"Organic ferroelectric field-effect transistors (Fe-OFETs) exhibit exceptional capabilities in mimicking biological neural systems and represent one of the primary options for flexible artificial synaptic devices. Ferroelectric polymers, such as poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)), given their strong ferroelectricity and facile solution processing, have emerged as the preferred choices for the ferroelectric dielectric layer of wearable devices. However, the solution processed P(VDF-TrFE) films can lead to high interface roughness, prone to cause excessive gate leakage. Meanwhile, the ferroelectric layer in neural computing and memory applications also faces a trade-off between storage time and energy for read/write operations. This study introduces a composite dielectric layer for Fe-OFETs, fabricated via a solution-based process. Different thicknesses of poly(N-vinylcarbazole) (PVK) are shown to significantly alter the ferroelectric hysteresis window and leakage current. The optimized devices exhibit synaptic plasticity with a transient current of 3.52 mA and a response time of approximately 50 ns. The Fe-OFETs with the composite dielectric were modeled and integrated into convolutional neural networks, achieving a 92.95% accuracy rate. This highlights the composite dielectric's advantage in neuromorphic computing. The introduction of PVK optimizes the interface and balances device performance of Fe-OFETs for neuromorphic computing.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"64 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142713303","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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