Young-Woong Song, Junseo Lee, Sein Lee, Wooho Ham, Jeong Hyun Yoon, Jeong-Min Park, Taehoon Sung, Jang-Yeon Kwon
{"title":"Linear Conductance Modulation in Aluminum Doped Resistive Switching Memories for Neuromorphic Computing","authors":"Young-Woong Song, Junseo Lee, Sein Lee, Wooho Ham, Jeong Hyun Yoon, Jeong-Min Park, Taehoon Sung, Jang-Yeon Kwon","doi":"10.1007/s13391-024-00516-w","DOIUrl":"10.1007/s13391-024-00516-w","url":null,"abstract":"<div><p>With the advent of artificial intelligence (AI), automated machines could replace human labor in the near future. Nevertheless, AI implementation is currently confined to environments with huge power supplies and computing resources. Artificial neural networks are only implemented at the software level, which necessitates the continual retrieval of synaptic weights among devices. Physically constructing neural networks using emerging nonvolatile memories allows synaptic weights to be directly mapped, thereby enhancing the computational efficiency of AI. While resistive switching memory (RRAM) represents superior performances for in-memory computing, unresolved challenges persist regarding its nonideal properties. A significant challenge to the optimal performance of neural networks using RRAMs is the nonlinear conductance update. Ionic hopping of oxygen vacancy species should be thoroughly investigated and controlled for the successful implementation of RRAM-based AI acceleration. This study dopes tantalum oxide-based RRAM with aluminum, thus improving the nonlinear conductance modulation during the resistive switching process. As a result, the simulated classification accuracy of the trained network was significant improved.</p><h3>Graphical Abstract</h3>\u0000<div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":536,"journal":{"name":"Electronic Materials Letters","volume":"20 6","pages":"725 - 732"},"PeriodicalIF":2.1,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141923615","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Hydrangea Macrophylla-Like CeO2 Coated by Nitrogen-Doped Carbon as Highly Efficient ORR Cathode Catalyst in a Hybrid Proton Battery","authors":"Rui Zhang, Huizhen Si, Qizhao Hu, Yangbo Cui, Shangbin Sang, Kaiyu Liu, Hongtao Liu, Qiumei Wu, Xianggong Zhang","doi":"10.1007/s13391-024-00515-x","DOIUrl":"10.1007/s13391-024-00515-x","url":null,"abstract":"<div><p>In this paper, nitrogen-doped carbon (NC) coated tens nanometer hydrangea macrophylla-like CeO<sub>2</sub>(CeO<sub>2</sub>-NC) was synthesized by simple hydrothermal and polymeric calcination approach. Samples are characterised by SEM, Raman spectroscopy, XPS, etc. CeO<sub>2</sub>-NC shows an initial potential of 0.90V (vs. Ag/AgCl) in 9.5 M H<sub>3</sub>PO<sub>4</sub>. In addition, the CeO<sub>2</sub>-NC composite also exhibits a high limiting current (6.25 mA mg<sup>−1</sup>). CeO<sub>2</sub>-NC effectively combines the high initial potential of CeO<sub>2</sub> with the high limiting current of NC. Moreover, a hybrid proton battery assembled with CeO<sub>2</sub>-NC composite as the cathode catalyst and MoO<sub>3</sub> (1 mg) as anode catalyst can produce a high capacity of 261.7 mAh at 1 A g<sup>−1</sup>. The hybrid battery also exhibits excellent catalytic stability. After 1000 cycles at a high current density of 15 A g<sup>−1</sup>, the capacity of the battery still remains 125.0 mAh, with a retention rate of approximately 90.9%. The improvement in battery performance is due to the use of NC to coat CeO<sub>2</sub>, which improves the limiting current and durability of the electrode. The presented hybrid proton batteries have further enriched the application of electrochemical energy storage devices, and the preliminary exploration of cathode catalysts significantly improved the catalytic performance of ORR under acidic conditions.</p><h3>Graphical Abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":536,"journal":{"name":"Electronic Materials Letters","volume":"20 6","pages":"807 - 817"},"PeriodicalIF":2.1,"publicationDate":"2024-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141932532","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Exploring the Electronic Structure and Magnetic Properties of Sm2MgMnO6 Double Perovskite","authors":"Samarendra Nath Saha, Purna Chandra Barman, N. Bedamani Singh, Rajkumar Mondal, Sk. Anirban","doi":"10.1007/s13391-024-00512-0","DOIUrl":"10.1007/s13391-024-00512-0","url":null,"abstract":"<div><p>In this article, we have investigated the electronic structure and magnetic properties of Sm<sub>2</sub>MgMnO<sub>6</sub> prepared through auto-combustion method. The first principles of the density-functional theory have been applied to study of the electronic structure. The oxidation states of Mn and Mg are Mn<sup>3+</sup>/Mn<sup>4+</sup> and Mg<sup>2+</sup>, respectively. The existence of Mn<sup>3+</sup> is higher than Mn<sup>4+</sup>. The magnetic study reveals the sample shows ferromagnetic to paramagnetic transition at around 13.5 K which is followed by an antiferromagnetic ordering at 8.3 K. Antiferromagnetic and ferromagnetic ordering have been identified at 8.3 K and higher temperature, respectively. Sm<sub>2</sub>MgMnO<sub>6</sub> shows a maximum magnetic entropy change of 1.25 J kg<sup>-1</sup>K<sup>-1</sup> and relative cooling power of 86.9 J/kg for a field variation of 70 kOe near 25 K. The values are comparable to many double perovskites reported previously. This study highlights that Sm<sub>2</sub>MgMnO<sub>6</sub> is a potential material for magnetocaloric refrigerant at low temperature.</p><h3>Graphical Abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":536,"journal":{"name":"Electronic Materials Letters","volume":"20 6","pages":"745 - 755"},"PeriodicalIF":2.1,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141863940","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Insights on Asymmetrical Electrode Geometric Effect to Enhance Gate-Drain-Bias Stability of Vertical-Channel InGaZnO Thin-Film Transistor","authors":"Dong-Hee Lee, Young-Ha Kwon, Nak-Jin Seong, Kyu-Jeong Choi, Jong-Heon Yang, Chi-Sun Hwang, Sung-Min Yoon","doi":"10.1007/s13391-024-00513-z","DOIUrl":"10.1007/s13391-024-00513-z","url":null,"abstract":"<div><p>The asymmetrical gate-drain bias stress (GDBS) stability of a mesa-shaped vertical-channel thin-film transistors (VTFTs) was investigated using an In-Ga-Zn–O (IGZO) active layer prepared by atomic-layer deposition. The GDBS measurements were conducted with variations in electrode configurations and overlapped areas between the active and bottom electrode regions. The GDBS stability of the IGZO VTFTs was found to be significantly degraded, when a plasma-damaged electrode was used as the drain electrode, due to the formation of defective channel regions that are more susceptible to the hot carrier effect. To address the effect of plasma-damaged electrode, an ultrathin passivation layer was introduced, resulting in the achievement of VTFTs with excellent and uniform GDBS stability.</p><h3>Graphical Abstract</h3>\u0000<div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":536,"journal":{"name":"Electronic Materials Letters","volume":"20 6","pages":"702 - 710"},"PeriodicalIF":2.1,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141863941","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jun Hu Park, Seung Min Joo, Tae Min Kim, Younghoon Kim, Hyun Ho Kim
{"title":"Synthesis of Ultrathin MoO2 Nanosheets via Chemical Vapor Deposition and Their Application to High-Performance Field-Effect Transistors","authors":"Jun Hu Park, Seung Min Joo, Tae Min Kim, Younghoon Kim, Hyun Ho Kim","doi":"10.1007/s13391-024-00511-1","DOIUrl":"10.1007/s13391-024-00511-1","url":null,"abstract":"<div><p>Two-dimensional (2D) transition metal dichalcogenides (TMDs) are excellent candidates for electronic applications because of their high carrier mobility, tunable bandgap energy depending on the number of layers, monolayer thickness, and the absence of dangling bonds on their surfaces. Despite these advantages, the crystalline structures of TMDs contain intrinsic defects such as vacancies, adatoms, grain boundaries, and substitutional impurities, which can cause large contact resistance at the source/drain interface. Customized engineering of interfaces and defects, which provides a method to modulate the properties of TMDs, is crucial as it can significantly enhance device performance. Herein, we explored a novel electrode to enhance the interface between electrode and semiconductor materials. we report the synthesis of high-quality atomically thin MoO<sub>2</sub> using atmospheric pressure chemical vapor deposition (APCVD) and its application to field-effect transistors. To improve crystallinity of MoO<sub>2</sub>, we investigated the influence of hydrogen concentration, a key parameter in the reduction process, on the synthesis of high-crystallinity MoO₂. By adding NaCl to MoO₃ powder, we optimized the synthesis of high-crystallinity MoO₂. Utilizing the optimized MoO₂, we fabricated transistors that exhibited a mobility of 29.1 cm²/V∙s and an on/off ratio of 1.78 × 10⁴, demonstrating excellent performance. Our findings confirm that single-crystal MoO<sub>2</sub> can be effectively applied as a contact electrode in high-performance two-dimensional semiconductor devices.</p></div>","PeriodicalId":536,"journal":{"name":"Electronic Materials Letters","volume":"20 6","pages":"818 - 826"},"PeriodicalIF":2.1,"publicationDate":"2024-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141775646","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Significant Mobility Enhancement by Semicrystalline Polymers Additive for Crystallization and Charge Transport in Organic Field-effect Transistor","authors":"Sheng Bi, Zehui Yao, Xu Han, Congjie Bi, Xiaolong Wang, Qiangqiang Chen, Yao Wang, Rongyi Wang, Kyeiwaa Asare-Yeboah, Zhengran He, Ruonan Song","doi":"10.1007/s13391-024-00510-2","DOIUrl":"10.1007/s13391-024-00510-2","url":null,"abstract":"<div><p>The incorporation of semi-crystalline polymers as additives with small-molecule organic semiconductors has emerged as a pioneering method for the alteration of crystallization processes, thin film morphologies, and charge carrier mobility within organic semiconductor matrices. In this paper, we utilize the intrinsic attributes of polyethylene oxide (PEO), acting as a semi-crystalline polymer additive, to modulate the crystallization, phase segregation and charge transport of 6,13-bis (triisopropylsilyl) pentacene (TIPS pentacene). To understand the synergistic effects between varying molecular weights (8, 100, 300 and 900 K) of PEO and the crystallization behavior of TIPS pentacene, we conducted a quantitative analysis of the films' relative crystallinity and crystallographic morphology employing X-ray diffraction (XRD) and optical microscopy. Our findings indicate that higher molecular weight PEOs (300K and 900K) exhibit reduced molecular chain activity, resulting in lower crystallinity at increased doping ratios. Furthermore, attributes such as a high dielectric constant and a substantial melting point, combined with favorable thermoplastic properties, predispose these films to a more susceptible phase separation within the crystalline matrix. Conversely, films with lower molecular weight PEOs (8 and 100 K) showed lesser impact from molecular chain dynamics, leading to enhanced crystal morphology, higher crystallinity, and improved charge carrier mobility by up to 11 times. This substantial enhancement underscores the potential of employing low molecular weight semi-crystalline polymers as additive agents in the development of advanced organic semiconductor devices.</p><h3>Graphical Abstract</h3>\u0000<div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":536,"journal":{"name":"Electronic Materials Letters","volume":"20 6","pages":"711 - 724"},"PeriodicalIF":2.1,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141775645","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Dokyun Kim, Unggi Kim, Sungjae Choi, Young-Chang Joo
{"title":"Understanding the Electrical Characteristics of Electrochemical Metallization Memristors through Identification of Conduction Channel in Entire Active Area","authors":"Dokyun Kim, Unggi Kim, Sungjae Choi, Young-Chang Joo","doi":"10.1007/s13391-024-00509-9","DOIUrl":"10.1007/s13391-024-00509-9","url":null,"abstract":"<div><p>Physical observation of electrochemical metallization (ECM) channel is required for understanding the electrical characteristics of ECM memristors. Although numerous studies have explored to identify the ECM channels, the majority of approaches have been limited to in-situ systems and localized areas, lacking a comprehensive demonstration of their findings. This study focuses on interpreting the different electrical characteristics of ECM memristors through identification of ECM channels using a new method inspired by etch pit detection on Si surface for determining copper contamination. Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM) were utilized to detect and analyze conductive channels within the switching medium after real operation. Interestingly, devices with insulating amorphous carbon (a-C) as medium layer exhibited multiple channels, while devices with semiconducting a-C layers showed a single channel in the on-state. Furthermore, devices with a single channel demonstrated more uniform switching parameters, including high resistance state and set voltage, compared to devices with multiple channels. However, devices with multiple channels exhibited better retention properties .In addition, intermetallic conductive channels were confirmed, resulting from the mixing of Cu active metal ions with the Pt bottom electrode in high current density conditions. The findings of this work provide valuable insights into interpreting ECM memristor performance based on the formation of channels and inspire device design strategies for improving device performance.</p><h3>Graphical Abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":536,"journal":{"name":"Electronic Materials Letters","volume":"20 5","pages":"525 - 536"},"PeriodicalIF":2.1,"publicationDate":"2024-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141547018","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jae Young Hwang, Dokyun Kim, Hyejin Jang, So-Yeon Lee, Young-Chang Joo
{"title":"Thermal and Electrical Properties Depending on the Bonding Structure of Amorphous Carbon Thin Films","authors":"Jae Young Hwang, Dokyun Kim, Hyejin Jang, So-Yeon Lee, Young-Chang Joo","doi":"10.1007/s13391-024-00508-w","DOIUrl":"10.1007/s13391-024-00508-w","url":null,"abstract":"<div><p>Efficient heat energy management during operation remains a critical challenge in Phase Change Memory (PCM) devices. Reducing the thermal conductivity of electrodes has emerged as a promising strategy to address this issue. Amorphous carbon (a-C) thin films present an attractive option for PCM electrodes due to their intrinsically low thermal conductivity and tunable electrical properties. This study focuses on the development of a-C thin films with optimized electrical and thermal characteristics by controlling the sputtering pressure and conducting post-annealing treatments. Various analytical techniques, including X-ray photoelectron spectroscopy, time-of-flight secondary ion mass spectrometry, and Raman spectroscopy, were employed to investigate the microstructure and composition of the a-C thin films. The results demonstrate that the optimal condition for achieving improved electrical and thermal properties is at the lowest sputtering pressure (2.5 mTorr), which is attributed to the reduced impurity content (specifically oxygen and hydrogen) and denser film structure. Furthermore, post-annealing treatment at 400 °C for 30 min resulted in further improvements in thermal and electrical properties due to the formation of sp<sup>2</sup> clusters and the reduction of impurities within the film. Consequently, the post-annealed a-C thin film exhibited an outstanding low thermal conductivity of 1.34 W m<sup>−1</sup> K<sup>−1</sup> and an adequate electrical resistivity of 0.02 Ω cm. The findings of this work provide valuable insights into the underlying mechanisms governing the electrical and thermal properties of a-C thin films, paving the way for the development of energy-efficient PCM devices.</p><h3>Graphical Abstract</h3>\u0000<div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":536,"journal":{"name":"Electronic Materials Letters","volume":"20 5","pages":"648 - 656"},"PeriodicalIF":2.1,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141522278","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Effect of Deposition Temperature on the Electrical Properties of Solid-Phase Crystallized Ge Thin Films","authors":"Youngho Cho, Mingjun Jiang, Donghwan Ahn, Woong Choi","doi":"10.1007/s13391-024-00506-y","DOIUrl":"10.1007/s13391-024-00506-y","url":null,"abstract":"<div><p>We report the effect of deposition temperature, spanning from 30 °C to 200 °C, on the electrical properties of solid-phase crystallized Ge thin films on SiO<sub>2</sub>/Si substrates. Our findings revealed three distinct ranges of deposition temperature, each exhibiting unique electrical properties. The initial thin films were amorphous with low density in the first range (below 100 °C), amorphous with high density in the second range (between 100 °C and 160 °C), and crystalline with high density in the third range (above 160 °C). In the first and second ranges, an increase in deposition temperature led to a fivefold increase in Hall mobility. This was attributed to the enlarged grain size and reduced energy barrier at grain boundaries possibly owing to the reduced concentration of oxygen impurities. Grain boundary scattering dominated carrier transport in the first range, while diminished energy barrier in the second range effectively mitigated grain boundary scattering. In the third range, an increase in deposition temperature resulted in a decrease in the Hall mobility. This may be linked to the reduced grain size. These results demonstrate the profound impact of deposition temperature on tailoring the electrical properties of polycrystalline Ge thin films, with potential implications for semiconductor processing.</p></div>","PeriodicalId":536,"journal":{"name":"Electronic Materials Letters","volume":"20 6","pages":"694 - 701"},"PeriodicalIF":2.1,"publicationDate":"2024-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141505343","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}