Article
Chemistry, Physical
Aline Bastos de Paiva, Rafael Schio Wengenroth Silva, Marcio Peron Franco de Godoy, Luis Miguel Bolanos Vargas, Marcelos Lima Peres, Demetrio A. W. Soares, Victor Lopez-Richard
Summary: This study presents how the components of solid state transport in polycrystalline systems become sufficient conditions for the emergence of memory. Experimental results and a theoretical model are provided to support these findings, which have important implications for understanding and operating resistive memories.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Multidisciplinary Sciences
Darshika Khone, Sandeep Kumar, Mohammad Balal, Sudipta Roy Barman, Sunil Kumar, Abhimanyu Singh Rana
Summary: Highly transparent resistive-switching devices were fabricated and their characteristics could be tuned by adjusting the top electrode and film thickness.
SCIENTIFIC REPORTS
(2023)
Article
Materials Science, Multidisciplinary
Prabir Mahato, Methapettyparambu Purushothama Jayakrishnan, Arnaud Vena, Etienne Perret
Summary: This research article introduces a new technique for fabricating planar micro gap CBRAM RF devices. The technique involves laser-based PCB lithography, electroplating, and spin coating. Nafion is used as an ion conductor between the electroplated copper and nickel electrodes. The devices show good reliability, low resistance state, high maximum isolation, low insertion loss, and a figure of merit of 2.65 THz.
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
(2023)
Article
Chemistry, Analytical
Qijing Lin, Fuzheng Zhang, Na Zhao, Ping Yang
Summary: Two sandwiched ZnO/Metal/ZnO transparent conductive thin films with different intermediate layers were fabricated using magnetron sputtering technology. Comparative analysis showed that the addition of a Ti layer improved the overall properties of the ZnO(Ti/Cu) film compared to the ZnO(Cu) film with the same metal layer thickness. The effect of annealing temperature was also studied, revealing that although the carrier concentration did not always increase with temperature, the sheet resistances decreased due to increased mobility. The transmittance of ZnO(Cu) films increased with annealing temperature, while that of ZnO(Ti/Cu) films initially increased and then decreased. The optical band gap of ZnO(Cu) films increased with temperature, but was lower than that of ZnO(Ti/Cu) films, which first increased and then decreased. The figure of merit for the ZnO(Ti/Cu) film was better, indicating that its overall performance was superior, and annealing improved the performance of the film systems.
Article
Nanoscience & Nanotechnology
Kwang Hoon Jung, Changbong Yeon, Junjae Yang, Ye Ji Cheon, Jung Wook Lim, Sun Jin Yun
Summary: The study demonstrated a surfactant-free PVA-assisted exfoliation method to prepare ReS2-PVA nanocomposite films with excellent optoelectrical properties. Transparent photosensitive memristor synapse devices based on the ReS2-PVA film exhibited long-term memory storage and synaptic behavior.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Multidisciplinary Sciences
Zhi Chen, Jie Wang, Hongbo Wu, Jianming Yang, Yikai Wang, Jing Zhang, Qinye Bao, Ming Wang, Zaifei Ma, Wolfgang Tress, Zheng Tang
Summary: This study focuses on the key issue of high-efficiency indium tin oxide-free organic optoelectronic devices. It achieves high conductivity and low optical absorption losses in zinc oxide films through the photoinduced doping effect, and further improves the conductivity by using a stacking strategy.
NATURE COMMUNICATIONS
(2022)
Article
Materials Science, Multidisciplinary
Dahye Kim, Jiwoong Shin, Sungjun Kim
Summary: In this work, the characteristics of Ni/ZnO/n-type Si RRAM device under different compliance currents were studied, showing the best variability at higher compliance current (5 mA) and proposing the appropriate compliance current for device operation. Comprehensive evaluation of device characteristics was conducted through statistical analysis and validation.
Article
Materials Science, Multidisciplinary
B. L. Zhu, C. C. Wang, T. Xie, J. Wu, X. W. Shi
Summary: ZnO films were prepared with Zn/ZnO composite target using RF magnetron sputtering under different atmospheres and substrate temperatures. The effects of gas flow rate and substrate temperature on the properties of the films were investigated, showing that different ZnO films can be obtained under different conditions.
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
(2021)
Article
Materials Science, Multidisciplinary
K. Jagannadham, C. B. Parker, J. T. Glass
Summary: The study investigates the interaction between light and the bipolar characteristics of two-terminal devices synthesized with ZnO film. Three types of devices are built with different configurations. The changes in the bipolar characteristics are explained in terms of the control of defect mobility by the incidence of radiation. It is demonstrated that optical illumination of memristor device with transparent semiconducting oxides modulates the switching characteristics and enhances the number of device states, particularly in p-n junction devices.
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
(2023)
Article
Chemistry, Multidisciplinary
Maria N. Koryazhkina, Dmitry O. Filatov, Stanislav V. Tikhov, Alexey I. Belov, Dmitry A. Serov, Ruslan N. Kryukov, Sergey Yu. Zubkov, Vladislav A. Vorontsov, Dmitry A. Pavlov, Evgeny G. Gryaznov, Elena S. Orlova, Sergey A. Shchanikov, Alexey N. Mikhaylov, Sungjun Kim
Summary: The electrical characteristics and resistive switching properties of memristive devices using silicon oxide and titanium nitride as the insulator and electrode materials have been studied. The as-fabricated devices do not require electroforming, but their resistance state cannot be stored before thermal treatment. After the thermal treatment, the devices exhibit bipolar-type resistive switching with synaptic behavior, where filaments form in the insulator due to the effect of traps. These devices can be easily integrated with traditional analog-digital circuits to implement new-generation hardware neuromorphic systems.
Article
Chemistry, Physical
Seokyeon Yun, Chandreswar Mahata, Min-Hwi Kim, Sungjun Kim
Summary: The study explored the creation of a Ni/ZnO/TiN memristor device for emulating an artificial synapse in a neuromorphic system, characterized through various chemical and material analysis methods. The device exhibited multi-level resistive switching behavior, showcasing both short-term and long-term memory characteristics. Different parameters, such as voltage and time interval, were found to impact the conductance of the device during repetitive pulses.
APPLIED SURFACE SCIENCE
(2022)
Article
Chemistry, Physical
Yunseok Lee, Jiung Jang, Beomki Jeon, Kisong Lee, Daewon Chung, Sungjun Kim
Summary: This study demonstrates stable switching using AlSiOx as an alloyed insulator, evaluating the retention and endurance of multi-level cells through resistive switching characteristics analysis, and simulating the potentiation/depression curves of a neuromorphic device.
Article
Engineering, Electrical & Electronic
Mohamed Fikry, Mohamed Mohie, Menna Gamal, Ahmed Ibrahim, Gehad Genidy
Summary: The study investigates the superior control of sputtering deposition of ITO thin-films to enhance their physical properties, examining the effects of various sputter deposition conditions and thermal post-annealing. The research demonstrates the impact of Ar flow rates on the deposited films' surface roughness, electrical resistance, and optical transmittance, achieving optimal thin-films with high transparency and good conductivity. Additionally, it successfully initiates the semi-crystalline structure of previously amorphous deposited thin-films through critical post-annealing temperatures, achieving unprecedented levels of transparency and conductivity, making them viable candidates for transparent solar applications.
OPTICAL AND QUANTUM ELECTRONICS
(2021)
Article
Nanoscience & Nanotechnology
Ange Liang, Jingwei Zhang, Fang Wang, Yutong Jiang, Kai Hu, Xin Shan, Qi Liu, Zhitang Song, Kailiang Zhang
Summary: Flexible memristors based on HfOx were fabricated on PEN substrates to simulate various bio-synapse functions, showing robust flexibility and excellent performance. The device exhibited symmetrical, linear characteristics and excellent uniformity at low power consumption. Essential synaptic behaviors were achieved in the device.
Article
Materials Science, Multidisciplinary
Himadri Sekhar Das, Rajesh Das, Prasanta Kumar Nandi, Sajal Biring, Subir Kumar Maity
Summary: The study demonstrates that Ga-doped ZnO thin films can serve as a promising alternative anode material in OLEDs, replacing ITO and SnO2:F films. Experimental results show that ZnO:Ga films exhibit excellent performance in terms of transparency and electrical properties, suitable for OLEDs and other optoelectronic devices.
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
(2021)
Article
Physics, Applied
Min-Hui Chuang, Yiming Li, Seiji Samukawa
Summary: The study focuses on the impact of geometry effects on the energy band of well-aligned silicon nanopillars in a silicon-germanium matrix, with emphasis on the crucial role of nanopillar separation in manipulating the band structure.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2021)
Article
Engineering, Electrical & Electronic
Sailesh Rajasekaran, Firman Mangasa Simanjuntak, Sridhar Chandrasekaran, Debashis Panda, Aftab Saleem, Tseung-Yuen Tseng
Summary: The Ta2O5/WO3 double-layer wearable memristor synapse shows excellent recognition accuracy after a small number of training epochs. It has outstanding durability, withstanding extreme bending, high temperature, and water resistance.
IEEE ELECTRON DEVICE LETTERS
(2022)
Article
Chemistry, Analytical
Pragya Singh, Firman Mangasa Simanjuntak, Li-Lun Hu, Tseung-Yuen Tseng, Hsiao-Wen Zan, Jinn P. Chu
Summary: In this study, ZnO nanorod films were successfully grown on annealed ZnO seed layers at different ambient temperatures. The morphology of the nanorods was found to affect the gas sensing response to nitric oxide (NO) gas. Annealing treatment changed the seed layer's grain size and defect concentration and was responsible for the observed phenomenon. The devices exhibited good sensing response to NO concentration of 10 ppb and up to 100 ppb.
Article
Materials Science, Coatings & Films
Beibei Ge, Daisuke Ohori, Yi-Ho Chen, Takuya Ozaki, Kazuhiko Endo, Yiming Li, Jenn-Hwan Tarng, Seiji Samukawa
Summary: This study reports the fabrication of high-quality hafnium dioxide (HfO2) film using neutral beam enhanced atomic layer deposition (NBEALD) at room temperature. The film exhibited excellent properties with low contamination and ideal refractive index. Additionally, high-quality stacked HfO2/SiO2 gate oxide films were successfully fabricated at room temperature.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
(2022)
Article
Nanoscience & Nanotechnology
Firman Mangasa Simanjuntak, Julianna Panidi, Fayzah Talbi, Adam Kerrigan, Vlado K. Lazarov, Themistoklis Prodromakis
Summary: The insertion of a metal layer between an active electrode and a switching layer leads to the formation of a ternary oxide at the interface. The properties of this self-formed oxide are dependent on the Gibbs free energy of oxide formation of the metal (Delta G degrees(f)). The role of various ternary oxides in the switching behavior of conductive bridge random access memory (CBRAM) devices was investigated. The ternary oxide acts as a barrier layer that limits the mobility of metal cations in the cell, promoting stable switching. Choosing a metal layer with an appropriate Delta G degrees(f) is crucial for achieving reliable CBRAM devices.
Article
Physics, Applied
Firman Mangasa Simanjuntak, Takeo Ohno, Kana Minami, Seiji Samukawa
Summary: A Cu/ZnO/ITO resistive random access memory (RRAM) structure was employed to investigate the effect of neutral oxygen beams as a surface treatment on ZnO films. The treatment reduced defect concentration in the sputtered-ZnO film and improved the resistance change characteristics of the device. These results indicate the great potential of neutral oxygen beams in the development of RRAM devices using ZnO films.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2022)
Article
Physics, Applied
Om Kumar Prasad, Sridhar Chandrasekaran, Chin-Han Chung, Kow-Ming Chang, Firman Mangasa Simanjuntak
Summary: This study investigates the effect of annealing on the switching characteristics of memristor devices and finds that the properties of annealed films encourage the diffusion of metal species in the oxide. The increase in non-lattice oxygen and the structure of the conducting bridge play a crucial role in determining the switching stability of the devices.
APPLIED PHYSICS LETTERS
(2022)
Article
Chemistry, Multidisciplinary
Roman Anufriev, Daisuke Ohori, Yunhui Wu, Ryoto Yanagisawa, Laurent Jalabert, Seiji Samukawa, Masahiro Nomura
Summary: The high thermal conductivity of silicon limits the performance of silicon-based thermoelectric energy generators. Past theoretical works proposed reducing the thermal conductivity with nanopillars on silicon films. However, due to difficulties in nanofabrication and measurements, these predictions were never confirmed. In this work, we fabricated and measured silicon films with nanopillars as small as 12 nm in diameter. Our experiments showed that nanopillars do host resonant phonon modes, but thermal measurements revealed no significant difference compared to silicon membranes without nanopillars. These results contradict previous predictions, suggesting the need for refined simulations under realistic experimental conditions.
Article
Physics, Applied
Tomoki Harada, Daisuke Ohori, Kazuhiko Endo, Seiji Samukawa, Tetsuo Ikari, Atsuhiko Fukuyama
Summary: Thermal management is crucial for miniaturized semiconductor devices. In metal-oxide-semiconductor field-effect transistors, temperature rise due to heat generation can reduce electron mobility. By inserting nanostructures into the channel layer, temperature rise can be prevented and electron mobility can be maintained. The effect of nanostructure spacing on heat generation and carrier behavior of Si-NP/SiGe composite films was studied. The carrier lifetime was found to increase when the nanostructure spacing was comparable to the electron mean-free path.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Energy & Fuels
Aditya Saha, Ryuji Oshima, Daisuke Ohori, Takahiko Sasaki, Hirokazu Yano, Hidenori Okuzaki, Takashi Tokumasu, Kazuhiko Endo, Seiji Samukawa
Summary: PEDOT:PSS/Si hybrid photovoltaic cells are attracting attention as a simplified and democratized way of solar energy production. The control of the PEDOT/Si interface is crucial for improved performance and lifetimes of multijunction devices. The effects of the interfacial silicon oxide layer were investigated, and it was found that saturated interfacial silicon atoms and a thin, damage-free oxide interlayer were key for maintaining good passivation and high tunneling current. The interlayers with higher SiO2 content showed the least degradation.
Article
Nanoscience & Nanotechnology
Yi-Ho Chen, Daisuke Ohori, Muhammad Aslam, Yao-Jen Lee, Yiming Li, Seiji Samukawa
Summary: This study investigated the electrical properties of AlGaN/GaN high-electron-mobility transistors (HEMTs) with varied recess depths under the gate electrode. It was found that a recess depth of approximately 6 nm achieved through neutral beam etching (NBE) technique resulted in device enhancement-mode (E-mode) behavior with a threshold voltage (V-th) of 0.49 V. The study also examined the effects of post-metallization annealing (PMA) on device performance, showing improvements in various DC characteristics.
IEEE OPEN JOURNAL OF NANOTECHNOLOGY
(2023)
Article
Nanoscience & Nanotechnology
Seiji Samukawa
Summary: This paper reviews the author's work on a neutral beam process that suppresses the formation of defects at the atomic layer level, allowing for ideal surface chemical reactions to occur at room temperature. This technology is of great importance for creating innovative nano-devices in the future.
IEEE OPEN JOURNAL OF NANOTECHNOLOGY
(2022)
Article
Chemistry, Multidisciplinary
Bhaskar Pattanayak, Phuoc-Anh Le, Debashis Panda, Firman Mangasa Simanjuntak, Kung-Hwa Wei, Tan Winie, Tseung-Yuen Tseng
Summary: High-performance porous 3D graphene-based supercapacitors with ultra-high surface area and various-sized micropores were fabricated. The use of 1M KOH electrolyte resulted in the highest specific capacitance of the graphene electrode, which was achieved through counter ion adsorption, co-ion desorption, and ion permutation mechanisms. Symmetrical solid-state supercapacitors using graphene electrodes and PVA-KOH gel as the electrolyte exhibited excellent energy and power densities, as well as superior coulombic efficiency even after 6000 cycles.
Article
Engineering, Electrical & Electronic
Tahta Amrillah, My Ngoc Duong, Yu-Xun Chen, Yugandhar Bitla, Malik Anjelh Baqiya, Fitri Nur Indah Sari, Le Thi Quynh, Angga Hermawan, Firman Mangasa Simanjuntak, Chia-Hao Chen, Kaung-Hsiung Wu, Jenh-Yih Juang
Summary: YMO thin films exhibit distinctly different microstructures, electronic structures, and magnetic properties grown on substrates with different polarities, indicating the substantial influence of substrate surface polarity on film properties.
ACS APPLIED ELECTRONIC MATERIALS
(2022)
