{"title":"Physics of Ferroelectric Wurtzite Al1−xScxN Thin Films","authors":"Feng Yang","doi":"10.1002/aelm.202400279","DOIUrl":"https://doi.org/10.1002/aelm.202400279","url":null,"abstract":"Al<jats:sub>1−x</jats:sub>Sc<jats:sub>x</jats:sub>N emerges as a revolutionary ferroelectric material within the III‐N family. It combines exceptional switchable polarization (80–165 µC cm<jats:sup>−</jats:sup><jats:sup>2</jats:sup>), highly tunable coercive fields (1.5–6.5 MV cm<jats:sup>−</jats:sup>¹), and a wide bandgap (4.9–5.6 eV). Unlike conventional ferroelectrics, Al<jats:sub>1−x</jats:sub>Sc<jats:sub>x</jats:sub>N exhibits remarkable compatibility with both CMOS and III‐N technologies. It can be fabricated on plastic substrates at low temperatures, demonstrating excellent flexibility and biocompatibility. Remarkably, Al<jats:sub>1−x</jats:sub>Sc<jats:sub>x</jats:sub>N maintains superior performance in harsh environments due to its outstanding thermal stability (up to 1100 °C). These unique characteristics position Al<jats:sub>1−x</jats:sub>Sc<jats:sub>x</jats:sub>N as a highly promising candidate for a wide range of applications, including high‐performance memory, in‐memory computing, neuromorphic computing, and next‐generation wearable and implantable devices, particularly for operation in complex environments. Despite its potential, Al<jats:sub>1−x</jats:sub>Sc<jats:sub>x</jats:sub>N faces challenges such as high coercive fields, significant leakage currents, and limited polarization reversal cycle life. Addressing these challenges require a deeper understanding of the fundamental physics controlling Al<jats:sub>1−x</jats:sub>Sc<jats:sub>x</jats:sub>N films. This review explores the origins of Al<jats:sub>1−x</jats:sub>Sc<jats:sub>x</jats:sub>N's ferroelectricity and phase stability, delves into the fundamental theory of wurtzite ferroelectricity, investigates mechanisms for controlling spontaneous polarization and coercive fields, examines recent research progress in Al<jats:sub>1−x</jats:sub>Sc<jats:sub>x</jats:sub>N ferroelectric devices, and outlines future development directions for this exciting material.","PeriodicalId":110,"journal":{"name":"Advanced Electronic Materials","volume":"190 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142245734","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jiho Kim, Ohhyuk Kwon, Jongseon Seo, Hyunsang Hwang
{"title":"Vertical-Switching Conductive Bridge Random Access Memory with Adjustable Tunnel Gap and Improved Switching Uniformity Using 2D Electron Gas","authors":"Jiho Kim, Ohhyuk Kwon, Jongseon Seo, Hyunsang Hwang","doi":"10.1002/aelm.202400650","DOIUrl":"https://doi.org/10.1002/aelm.202400650","url":null,"abstract":"Owing to the high reactivity and diffusivity of Ag and Cu ions, controlling the atomic filament formation and rupture processes in conductive bridge random-access memory (CBRAM) is challenging. In this study, it is demonstrated that by using a 2D electron gas (2DEG) as the bottom electrode (BE) in a vertical-switching CBRAM (V-CBRAM), filament formation and rupture can be effectively managed and the tunnel gap distance created by partial filament formation can be adjusted. The 2DEG BE induces partial filament formation by limiting the number of electrons required for this process in the V-CBRAM device, as verified via current fitting to the quantum point contact model. Varying the electron concentration and activation energy for electrons trapped in the 2DEG, when paired with various programming voltages, leads to transitions in the device resistance state via changes in the distance of the tunnel gap. This tunnel-gap-tunable 2DEG V-CBRAM device, which exhibits superior switching uniformity, can be employed for nonvolatile memory applications in the sub-G<sub>0</sub> conductance regime, such as 3-bit multilevel cells and selector-less memory.","PeriodicalId":110,"journal":{"name":"Advanced Electronic Materials","volume":"38 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142237078","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Johanna Nordlander, Bastien F. Grosso, Marta D. Rossell, Aline Maillard, Bixin Yan, Elzbieta Gradauskaite, Nicola A. Spaldin, Manfred Fiebig, Morgan Trassin
{"title":"Combined Electrostatic and Strain Engineering of BiFeO3 Thin Films at the Morphotropic Phase Boundary","authors":"Johanna Nordlander, Bastien F. Grosso, Marta D. Rossell, Aline Maillard, Bixin Yan, Elzbieta Gradauskaite, Nicola A. Spaldin, Manfred Fiebig, Morgan Trassin","doi":"10.1002/aelm.202400185","DOIUrl":"https://doi.org/10.1002/aelm.202400185","url":null,"abstract":"Multiferroic BiFeO<sub>3</sub> exhibits a morphotropic phase boundary at large compressive strain that merges metastable phases of tetragonal (T) and rhombohedral (R) character resulting in giant ferroelectric and electromechanical responses. To utilize this functionality in devices, it is essential to understand the response of these ferroelectric phases to the environment of a nanoscale heterostructure. Here, the emergence of ferroelectricity near the morphotropic phase boundary in BiFeO<sub>3</sub> is explored directly during thin-film growth, using optical second harmonic generation. It is found that the epitaxial films form at the growth temperature purely in the T phase with zero critical thickness for the spontaneous polarization. Signatures of monoclinic T-like and R-like phases only appear upon sample cooling. The robustness of a single-domain configuration in the high-temperature T phase is furthermore demonstrated during growth of capacitor-like metal | ferroelectric | metal heterostructures. Here, a reduction in tetragonality, rather than multidomain formation, lowers the electrostatic energy in the few-unit-cell thickness regime. For this lower tetragonality, density-functional calculations and scanning transmission electron microscopy point to the stabilization of a novel metastable monoclinic structure upon cooling toward room temperature. The synergistic combination of strain and electrostatic phase stabilization in BiFeO<sub>3</sub> heterostructures hence provides a basis for designing new ferroelectric phases and ultrathin ferroelectric devices.","PeriodicalId":110,"journal":{"name":"Advanced Electronic Materials","volume":"98 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142237074","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Formation of Conjugated Polymer Monolayer Networks on Water Surface and Nonlinear Charge Transport","authors":"Yuya Ishizaki-Betchaku, Naoki Hara, Taikai Matsuda, Jun Matsui, Takahiro Seki, Shusaku Nagano","doi":"10.1002/aelm.202400427","DOIUrl":"https://doi.org/10.1002/aelm.202400427","url":null,"abstract":"Material-networked conduction paths provide nonlinear electronic properties, which are essential components of computing and physically mimic the brain. In this study, the formation of conjugated polymer monolayer networks and their nonlinear charge transport is demonstrated. Poly(3-hexylthiophene) (P3HT) monolayer networks doped with 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ) is fabricated using the co-spread method with an amphiphilic liquid crystal molecule at the air–water interface. Atomic force microscopy and Ultraviolet–visible–near-infrared absorption spectroscopy measurements reveal the network surface morphologies and doped electronic states. The correlation between the nonlinear electronic characteristics and network structures of the P3HT/F4TCNQ monolayer networks is further systematically investigated through current–voltage and voltage–time measurements for various doping levels, network densities, and numbers of transferred layers. The current–voltage characteristics of the P3HT/F4TCNQ monolayer network device with a simple two-terminal structure exhibit nonlinear and ohmic conduction behavior, which depend strongly on the network density and geometric dimension (number of transferred layers). It is concluded that the nonlinear properties arise from the limited and unique network of 2D conduction passes. This study highlights the unique features of conducting polymer monolayer networks, paving the way for neuromorphic device applications including conjugated semiconducting polymer-based material reservoirs with controllable nanostructures.","PeriodicalId":110,"journal":{"name":"Advanced Electronic Materials","volume":"63 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142237076","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Toward Enhanced Biomimetic Artificial Visual Systems Based on Organic Heterojunction Optoelectronic Synaptic Transistors","authors":"Haonan Wang, Wandi Chen, Wenjuan Su, Zhenyou Zou, Shuchen Weng, Xiongtu Zhou, Chaoxing Wu, Tailiang Guo, Yongai Zhang","doi":"10.1002/aelm.202400632","DOIUrl":"https://doi.org/10.1002/aelm.202400632","url":null,"abstract":"Artificial visual systems, inspired by the human eye, hold significant potential in artificial intelligence. Optoelectronic synapses, integrating image perception, processing, and memory in a single device, offer promising solutions. The human eye exhibits different recognition accuracies for objects under varying light conditions. Therefore, a more biomimetic visual system is needed to better fit actual application scenarios. Here, an organic heterojunction-based optoelectronic synaptic transistor (OHOST) is proposed to enhance biomimetic artificial visual systems. By utilizing the excellent carrier capture ability of core-multi-shell quantum dots (QDs) and the high exciton dissociation efficiency of heterojunction interfaces, the device achieves a recognition capability under different light intensities closely resembling that of the human eye. Under optimal light intensity, the recognition accuracy for the modified national institute of standards and technology (MNIST) dataset can reach 91.52%. Nevertheless, under both low and high light intensities, the accuracy drops to a low level. This work pushes the development of artificial visual systems toward higher levels of biomimicry.","PeriodicalId":110,"journal":{"name":"Advanced Electronic Materials","volume":"46 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142237077","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Intrinsically Stable Charged Domain Walls in Molecular Ferroelectric Thin Films","authors":"Xin Li, Cheng Li, Linming Zhou, Xiangwei Guo, Yuhui Huang, Hui Zhang, Shurong Dong, Yongjun Wu, Zijian Hong","doi":"10.1002/aelm.202400324","DOIUrl":"https://doi.org/10.1002/aelm.202400324","url":null,"abstract":"Charged domain walls in ferroelectrics hold great promise for applications in ferroelectric random‐access memory (FeRAM), with advantages such as low energy consumption, high density, and non‐destructive operation. Due to the mechanical compatibility condition, the neutral domain walls are dominant in traditional ferroelectric thin films. Herein, using phase‐field simulations, the formation of intrinsically stable charged domain walls (CDWs) in the molecular ferroelectric films is demonstrated, which can be mainly attributed to the small mechanical stiffness. The switching kinetics are further investigated for the CDWs, showing a lower switching barrier as compared to the neutral counterparts. Moreover, it is indicated that increasing the compressive misfit strain can lead to prolonged switching time, with a significantly increased switching energy barrier. These findings pave the way for the potential applications of metal‐free organic ferroelectric materials in FeRAM devices.","PeriodicalId":110,"journal":{"name":"Advanced Electronic Materials","volume":"7 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142236483","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abdullah H. Alshehri, Hatameh Asgarimoghaddam, Louis‐Vincent Delumeau, Viet Huong Nguyen, AlRasheed Ali, Mutabe Aljaghtham, Ali Alamry, Dogu Ozyigit, Mustafa Yavuz, Kevin P. Musselman
{"title":"Combinatorial Optimization of Metal‐Insulator‐Insulator‐Metal (MIIM) Diodes With Thickness‐Gradient Films via Spatial Atomic Layer Deposition","authors":"Abdullah H. Alshehri, Hatameh Asgarimoghaddam, Louis‐Vincent Delumeau, Viet Huong Nguyen, AlRasheed Ali, Mutabe Aljaghtham, Ali Alamry, Dogu Ozyigit, Mustafa Yavuz, Kevin P. Musselman","doi":"10.1002/aelm.202400093","DOIUrl":"https://doi.org/10.1002/aelm.202400093","url":null,"abstract":"Metal‐insulator‐insulator‐metal (MIIM) diodes with thickness‐gradient films for the insulator layers are fabricated for the first time. Spatially varying atmospheric‐pressure chemical vapor deposition is used to deposit ZnO and Al<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> films with orthogonal gradient directions, producing 414 MIIM diodes with 414 different ZnO/Al<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> film‐thickness combinations on a single substrate for combinatorial and high‐throughput optimization. The nm‐scale ZnO/Al<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> films are printed in only 2 min and the entire device fabrication takes 7 h, which is much less than conventional approaches for investigating many insulator‐thickness combinations. Rapid identification of the optimal thickness combination is demonstrated; high‐performance diodes (asymmetry = 227, nonlinearity = 13.1, and responsivity = 12 A/W) are observed when a trap‐assisted tunneling mechanism is dominant for insulator thicknesses of 3.4–4.4 nm (ZnO) and 7.4 nm (Al<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub>).","PeriodicalId":110,"journal":{"name":"Advanced Electronic Materials","volume":"33 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142236482","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rui Jia, Xiaozheng Duan, Kaige Wang, Fengqiang Sun, Teng Li, Zhu Chen, Le Wang, Gang Wang, Liang-Wen Feng, Hengda Sun, Meifang Zhu
{"title":"Training-Augmented Ionic Switch for Logic Signal Modulation","authors":"Rui Jia, Xiaozheng Duan, Kaige Wang, Fengqiang Sun, Teng Li, Zhu Chen, Le Wang, Gang Wang, Liang-Wen Feng, Hengda Sun, Meifang Zhu","doi":"10.1002/aelm.202400408","DOIUrl":"https://doi.org/10.1002/aelm.202400408","url":null,"abstract":"Efficient ionic conductivity switching is crucial for the progression of iontronics, where adaptability and dynamic control are desirable to the innovation of intelligent devices. One of the main challenges in the field is to develop materials that not only transit between distinct conductive states but also exhibit evolvable properties to enhance their functional capabilities. Addressing this, a reversible phase-transition hydrated salt crystal ionic gel (RPSIG) for innovative ionic switch design is introduced. The RPSIG demonstrates an exceptional ability to modulate its ionic conductivity, with a switching ratio able to reach 5000-fold after training. The training effect can be attributed to the enhanced synergistic interplay between crystallites and the polymer matrix, which leads to thermodynamic stabilization of the interfacial structure and induces a higher energy cost for ion migrations. Meanwhile, the RPSIG exhibits the capability to adjust its resistive-capacitive properties in response to phase transitions, making it a versatile component for signal processing. Further application of RPSIG in intelligent latches and multifunctional hybrid circuits enables effective logic signal transmission, highlighting its potential in pioneering the development of advanced iontronic devices.","PeriodicalId":110,"journal":{"name":"Advanced Electronic Materials","volume":"17 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142171175","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zhuoqun Fang, Melissa Alzate-Banguero, Amit R. Rajapurohita, Forrest Simmons, Erica W. Carlson, Zhuoying Chen, Lionel Aigouy, Alexandre Zimmers
{"title":"Tuning the Resistance of a VO2 Junction by Focused Laser Beam and Atomic Force Microscopy","authors":"Zhuoqun Fang, Melissa Alzate-Banguero, Amit R. Rajapurohita, Forrest Simmons, Erica W. Carlson, Zhuoying Chen, Lionel Aigouy, Alexandre Zimmers","doi":"10.1002/aelm.202400249","DOIUrl":"https://doi.org/10.1002/aelm.202400249","url":null,"abstract":"Vanadium Dioxide (VO<sub>2</sub>) is a material that exhibits a phase transition from an insulating state to a metallic state at ≈68 °C. During a temperature cycle consisting of warming followed by cooling, the resistivity of VO<sub>2</sub> changes by several orders of magnitude over the course of the hysteresis loop. Using a focused laser beam (λ = 532 nm), it is shown that it is possible to optically generate micron-sized metallic patterns within the insulating phase of a VO<sub>2</sub> planar junction which can be used to tune, on demand, the resistance of the VO<sub>2</sub> junction. A resistor network simulation is used to characterize the resulting resistance drops in the devices. These patterns persist while the base temperature is held constant within the hysteretic region while being easily removed totally by simply lowering the base temperature. Surprisingly, it is also observed that the pattern can be partially erased using an atomic force microscope (AFM) tip on the submicron scale. This erasing process can be qualitatively explained by the temperature difference between the VO<sub>2</sub> surface and the tip which acts as a local cooler. This optical and AFM resistive fine-tuning offers the possibility of creating controllable synaptic weights between room-temperature VO<sub>2</sub> neuristors.","PeriodicalId":110,"journal":{"name":"Advanced Electronic Materials","volume":"49 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142166042","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Felix V.E. Hensling, Patrick Vogt, Jisung Park, Shun-Li Shang, Huacheng Ye, Yu-Mi Wu, Kathleen Smith, Veronica Show, Kathy Azizie, Hanjong Paik, Debdeep Jena, Huili G. Xing, Y. Eren Suyolcu, Peter A. van Aken, Suman Datta, Zi-Kui Liu, Darrell G. Schlom
{"title":"Fully Transparent Epitaxial Oxide Thin-Film Transistor Fabricated at Back-End-of-Line Temperature by Suboxide Molecular-Beam Epitaxy","authors":"Felix V.E. Hensling, Patrick Vogt, Jisung Park, Shun-Li Shang, Huacheng Ye, Yu-Mi Wu, Kathleen Smith, Veronica Show, Kathy Azizie, Hanjong Paik, Debdeep Jena, Huili G. Xing, Y. Eren Suyolcu, Peter A. van Aken, Suman Datta, Zi-Kui Liu, Darrell G. Schlom","doi":"10.1002/aelm.202400499","DOIUrl":"https://doi.org/10.1002/aelm.202400499","url":null,"abstract":"Transparent oxide thin film transistors (TFTs) are an important ingredient of transparent electronics. Their fabrication at the back-end-of-line (BEOL) opens the door to novel strategies to more closely integrate logic with memory for data-intensive computing architectures that overcome the scaling challenges of today's integrated circuits. A recently developed variant of molecular-beam epitaxy (MBE) called suboxide MBE (S-MBE) is demonstrated to be capable of growing epitaxial In<sub>2</sub>O<sub>3</sub> at BEOL temperatures with unmatched crystal quality. The fullwidth at halfmaximum of the rocking curve is 0.015° and, thus, ≈5x narrower than any reports at any temperature to date and limited by the substrate quality. The key to achieving these results is the provision of an In<sub>2</sub>O beam by S-MBE, which enables growth in adsorption control and is kinetically favorable. To benchmark this deposition method for TFTs, rudimentary devices were fabricated.","PeriodicalId":110,"journal":{"name":"Advanced Electronic Materials","volume":"59 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142166046","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}