Article
Chemistry, Multidisciplinary
Jingyun Zou, Zhengyang Cai, Yongjue Lai, Junyang Tan, Rongjie Zhang, Simin Feng, Gang Wang, Junhao Lin, Bilu Liu, Hui-Ming Cheng
Summary: The study presents an in-situ chemical vapor deposition method that allows for widely tunable doping concentrations in monolayer MoS2. By using appropriate vanadium precursors with different doping abilities, large-scale uniform doping to MoS2 can be achieved. Artificial synaptic transistors were fabricated using heavily doped MoS2, mimicking synaptic potentiation, depression, and repetitive learning processes.
Article
Materials Science, Multidisciplinary
Deepu Kumar, Vivek Kumar, Rahul Kumar, Mahesh Kumar, Pradeep Kumar
Summary: Probing phonons, quasiparticle excitations, and their coupling in monolayer and bilayer MoSe2, the researchers found the significant role of electron-phonon coupling, especially for the out-of-plane and shear modes. They also clarified the ambiguity in symmetry assignments and extracted the temperature-dependent thermal expansion coefficient.
Article
Nanoscience & Nanotechnology
Lily J. Stanley, Hsun-Jen Chuang, Zhixian Zhou, Michael R. Koehler, Jiaqiang Yan, David G. Mandrus, Dragana Popovic
Summary: The fabrication of hBN-encapsulated multiterminal WSe2 devices with 2D/2D low-temperature Ohmic contacts allows for investigation of the 2D metal-insulator transition. The devices exhibit Ohmic behavior down to 0.25 K and enable accurate determination of carrier density. Measurements show scaling behavior consistent with a metal-insulator quantum phase transition driven by electron-electron interactions and disorder-induced local magnetic moments.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Chemistry, Physical
Jianjun Deng, Zhonghao Zhou, Jinglong Chen, Zhihai Cheng, Jia Liu, Zhiyong Wang
Summary: In this study, vanadium-doped molybdenum selenide, a new diluted magnetic semiconductor, was synthesized using a single-step chemical vapor deposition method. The material showed both semiconductor characteristics and ferromagnetism at room temperature. The study also investigated the effects of doping and nearby atoms on the material properties, providing future prospects for multifunctional applications of two-dimensional materials.
Article
Chemistry, Multidisciplinary
Azimkhan Kozhakhmetov, Samuel Stolz, Anne Marie Z. Tan, Rahul Pendurthi, Saiphaneendra Bachu, Furkan Turker, Nasim Alem, Jessica Kachian, Saptarshi Das, Richard G. Hennig, Oliver Groning, Bruno Schuler, Joshua A. Robinson
Summary: This study reports the successful scalable growth and vanadium doping of 2D WSe2 at compatible temperatures, confirming p-type doping via substitutional replacement of tungsten by vanadium atoms. The p-type nature of the V dopants is further verified by constructed field-effect transistors.
ADVANCED FUNCTIONAL MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Changhyun Ko
Summary: Researchers have discovered that the optical, optoelectronic, and electric characteristics of monolayer molybdenum disulfide can be controlled through defect-induced doping. By using focused laser irradiation, the photoluminescence intensity of monolayer molybdenum disulfide was increased by approximately 1500%. Nano-Auger electron spectroscopy revealed changes in the photoluminescence peaks. This study provides a facile, effective, and cost-efficient approach for exploring defect effects in two-dimensional structures.
APPLIED SCIENCES-BASEL
(2023)
Article
Chemistry, Multidisciplinary
Leo Yu, Minda Deng, Jingyuan Linda Zhang, Sven Borghardt, Beata Kardynal, Jelena Vuckovic, Tony F. Heinz
Summary: Atomically thin semiconductors offer an attractive platform for quantum emitters, although reported quantum emitters in these materials have relied on spin-forbidden transitions. By employing strain confinement in monolayer MoSe2, engineered quantum emitters with radiative rates exceeding those of other solid-state systems have been produced.
Article
Materials Science, Multidisciplinary
Dae Hyun Jung, Sang-il Kim, TaeWan Kim
Summary: The study reports the quantitative contact resistance and the Schottky barrier height of chemical vapor deposition grown-monolayer tungsten diselenide (WSe2)-based field-effect transistors (FETs) with Au electrodes, showing p-type behavior with certain mobility and on/off ratio.
Article
Chemistry, Multidisciplinary
Xinyu Wang, Xinyu Chen, Jingyi Ma, Saifei Gou, Xiaojiao Guo, Ling Tong, Junqiang Zhu, Yin Xia, Die Wang, Chuming Sheng, Honglei Chen, Zhengzong Sun, Shunli Ma, Antoine Riaud, Zihan Xu, Chunxiao Cong, Zhijun Qiu, Peng Zhou, Yufeng Xie, Lifeng Bian, Wenzhong Bao
Summary: This article introduces the fabrication of MoS2 field-effect transistors with consistent performance using a 4-inch high-quality monolayer MoS2 film, and explores the design and fabrication of basic circuits and more complex logic circuits.
ADVANCED MATERIALS
(2022)
Article
Nanoscience & Nanotechnology
Po-Cheng Tsai, Coung-Ru Yan, Shoou-Jinn Chang, Shih-Yen Lin
Summary: Bottom-gate transistors with mono-layer MoS2 channels and polycrystalline antimonene source/drain contact electrodes are successfully fabricated. The devices exhibit significant improvement in performance, including high field-effect mobility and large ON/OFF ratio. Moreover, increased photocurrents are observed in the MoS2 transistor under light irradiation.
Article
Chemistry, Multidisciplinary
Bolun Wang, Xuewen Wang, Enze Wang, Chenyu Li, Ruixuan Peng, Yonghuang Wu, Zeqin Xin, Yufei Sun, Jing Guo, Shoushan Fan, Chen Wang, Jianshi Tang, Kai Liu
Summary: This study presents a synaptic transistor that can operate at high temperatures, using MoS2 and Na+-diffused SiO2 as the main materials, achieving high on/off ratio and recognition accuracy.
Article
Chemistry, Multidisciplinary
Preeti K. Poddar, Yu Zhong, Andrew J. Mannix, Fauzia Mujid, Jaehyung Yu, Ce Liang, Jong-Hoon Kang, Myungjae Lee, Saien Xie, Jiwoong Park
Summary: Photolithography and electron-beam lithography are commonly used methods for making nanoscale devices, but they disturb the electrical properties of 2D materials. We propose a resist-free lithography method using laser patterning and resist-free electrode transfer, which avoids unintentional modification to the 2D materials. This method enables the fabrication of large arrays of field-effect transistors and reveals the impact of solvents on the electrical conductivity of MoS2.
Article
Chemistry, Multidisciplinary
Taro Sasaki, Keiji Ueno, Takashi Taniguchi, Kenji Watanabe, Tomonori Nishimura, Kosuke Nagashio
Summary: Two-dimensional heterostructures have been extensively studied as NVM devices, but their operation mechanisms are not fully understood. Detailed operation mechanisms have been elucidated by exploiting FG voltage measurements, revealing three current-limiting paths controlling tunneling behavior between the channel and FG, and emphasizing the importance of the access region in achieving 2D channel/FG tunneling.
Article
Nanoscience & Nanotechnology
Keigo Matsuyama, Ryuya Aoki, Kohei Miura, Akito Fukui, Yoshihiko Togawa, Takeshi Yoshimura, Norifumi Fujimura, Daisuke Kiriya
Summary: This study investigates the modulation of carrier transport behavior in monolayer and multilayer MoS2 through surface charge transfer doping with benzyl viologen molecules. The metallic behavior transitions to an insulative state under negative gate voltage, exhibiting a metal-insulator transition. These findings provide insights into device characteristics of thin-layered materials and controlling phases via carrier modulation.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Chemistry, Physical
Zheng Wei, Jian Tang, Xuanyi Li, Zhen Chi, Yu Wang, Qinqin Wang, Bo Han, Na Li, Biying Huang, Jiawei Li, Hua Yu, Jiahao Yuan, Hailong Chen, Jiatao Sun, Lan Chen, Kehui Wu, Peng Gao, Congli He, Wei Yang, Dongxia Shi, Rong Yang, Guangyu Zhang
Summary: This study achieved uniform oxygen doping of wafer-scale monolayer MoS2 and found a reduction in bandgaps with increased oxygen-doping levels. Devices fabricated based on these doped MoS2 monolayers demonstrated excellent electronic performances, showing promise for their potential large-scale applications in electronics.
Article
Chemistry, Multidisciplinary
Timothy D. Brown, Stephanie M. Bohaichuk, Mahnaz Islam, Suhas Kumar, Eric Pop, R. Stanley Williams
Summary: This study presents a model of VO2/SiN Mott threshold switches constructed using the principle of local activity. The model is refined to measurable material properties by considering a minimal set of quasistatic and dynamic electrical and thermal data. It accurately predicts electrical and thermal conductivities and capacitances, as well as locally active dynamics.
ADVANCED MATERIALS
(2023)
Article
Nanoscience & Nanotechnology
Yang Li, Wei Wang, Di Zhang, Maria Baskin, Aiping Chen, Shahar Kvatinsky, Eilam Yalon, Lior Kornblum
Summary: Resistive switching devices, utilizing a simple and scalable material system of conductive oxide interfaces, have been developed for memory and computation. These devices offer advantages in performance and energy efficiency, and the conductive oxide interface serves both as the bottom electrode and as a reservoir of defects for switching. This new device, based on scalable and CMOS-compatible fabrication processes, opens up new design possibilities.
ADVANCED ELECTRONIC MATERIALS
(2023)
Article
Engineering, Electrical & Electronic
Sumaiya Wahid, Alwin Daus, Jimin Kwon, Shengjun Qin, Jung-Soo Ko, H. -S. Philip Wong, Eric Pop
Summary: We report the performance and gate bias stress stability of ultrathin (similar to 4 nm) channel indium tin oxide (ITO) transistors using different precursors for atomic layer deposition (ALD) of the Al2O3 top-gate dielectric. Water-based ALD leads to devices remaining in the on-state, while ozone-based ALD devices have less negative V-T shift at short channel lengths and relatively more positive V-T at all channel lengths. We achieve maximum drive current and good gate bias stability with normalized VT shift, improving over previous reports of uncapped ITO transistors.
IEEE ELECTRON DEVICE LETTERS
(2023)
Article
Engineering, Electrical & Electronic
Emanuel Ber, Ryan W. Grady, Eric Pop, Eilam Yalon
Summary: This article explores the issue of contact resistance in atomically thin 2-D semiconductors, which hinders the integration of these materials into mainstream technology. The resistance is found to be influenced by the height and width of the Schottky barrier, as well as the number of transport modes for carrier injection. To reduce the contact resistance, a large number of transport modes can be achieved by increasing the number of channel carriers through heavy doping or gating.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Physics, Applied
Qinshu Li, Or Levit, Eilam Yalon, Bo Sun
Summary: The thermal conductivity of amorphous, cubic, and hexagonal Ge2Sb2Te5 has been measured using time-domain thermoreflectance. The results show different thermal conductivities for each phase, with the hexagonal phase having the highest value. These findings are important for improving the thermal design of phase change memory devices and achieving more energy-efficient non-volatile memory.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Chemistry, Multidisciplinary
Mor Mordechai Dahan, Halid Mulaosmanovic, Or Levit, Stefan Dunkel, Sven Beyer, Eilam Yalon
Summary: The discovery of ferroelectric doped HfO2 enables the development of scalable and CMOS-compatible ferroelectric field-effect transistor (FeFET) technology, which has the potential to meet the demand for fast, low-power, low-cost, and high-density nonvolatile memory and neuromorphic devices. This study demonstrates that a single subnanosecond pulse can fully switch HfO2-based FeFET, revealing the high-speed capabilities of FeFETs and shedding light on the fundamental polarization switching speed limits and kinetics.
Article
Nanoscience & Nanotechnology
Emanuel Ber, Ryan W. Grady, Eric Pop, Eilam Yalon
Summary: Achieving good electrical contacts is a major challenge in devices based on atomically thin 2D semiconductors. This study experimentally examines the classical transmission line model description of contacts to 2D materials and proposes a modification based on an additional lateral resistance component. It finds that the additional lateral resistance component dominates the contact resistance in atomically thin semiconductor devices and is responsible for the back-gate bias and temperature dependence.
ADVANCED ELECTRONIC MATERIALS
(2023)
Article
Nanoscience & Nanotechnology
Il-Kwon Oh, Asir Intisar Khan, Shengjun Qin, Yujin Lee, H. -S. Philip Wong, Eric Pop, Stacey F. Bent
Summary: This study explores the application of area-selective atomic layer deposition (AS-ALD) technique in the fabrication of RRAM devices and finds that AS-ALD can improve the reliability and accuracy of RRAM, regardless of device size. The application of this technique will contribute to the improvement of other data storage technologies.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Chemistry, Multidisciplinary
Christopher Perez, Aaron J. Mcleod, Michelle E. Chen, Su-In Yi, Sam Vaziri, Ryan Hood, Scott T. Ueda, Xinyu Bao, Mehdi Asheghi, Woosung Park, A. Alec Talin, Suhas Kumar, Eric Pop, Andrew C. Kummel, Kenneth E. Goodson
Summary: Aluminum nitride (AlN) is an electrically insulating material with excellent thermal conductivity. This study demonstrates the deposition of AlN films at low temperatures using sputtering, and analyzes their thermal properties based on grain size and interfacial quality. The results show that varying the partial pressure of reactive N2 can significantly alter the thermal conductivity of the films, and the defect densities can be estimated from the measurements, providing insights for optimizing the thermal engineering of AlN.
Review
Engineering, Electrical & Electronic
Divya Somvanshi, Satyabrata Jit
Summary: The unique properties of two-dimensional materials have allowed for the exploration of novel phenomena in optoelectronic applications. These materials can be combined with other dimensional materials to form mixed-dimensional heterostructures without the need for direct chemical bonding. This article provides a critical review of recent research on mixed-dimensional heterostructures-based photodetectors, discussing their types and fundamental issues related to band alignment, interlayer coupling, and charge and energy transfer for photodetection applications.
MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
(2023)
Article
Engineering, Electrical & Electronic
Sayantika Chowdhury, Amodini Mishra, P. Venkateswaran, Divya Somvanshi
Summary: In this study, we designed a 2D heterostructure based on GaTe and MoTe2 monolayers to enhance their performance for optoelectronic and energy applications. Hybrid-DFT calculations were performed to investigate the electronic structure and optical spectra of the GaTe/MoTe2 heterostructure under external strain and electric field. It was found that the heterostructure exhibited a type II band alignment and high optical absorption, indicating its potential for next-generation applications.
MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
(2023)
Article
Nanoscience & Nanotechnology
Aviv Schwarz, Hadas Alon-Yehezkel, Adi Levi, Rajesh Kumar Yadav, Koushik Majhi, Yael Tzuriel, Lauren Hoang, Connor S. Bailey, Thomas Brumme, Andrew J. Mannix, Hagai Cohen, Eilam Yalon, Thomas Heine, Eric Pop, Ori Cheshnovsky, Doron Naveh
Summary: Recent research on 2D transition metal dichalcogenides (TMDCs) has led to important discoveries in fundamental phenomena and device applications. In this study, a two-step treatment with organic molecules was used to heal native defects in CVD-grown WSe2 and WS2. The adsorption of thiols was found to only partially passivate defects, but molecular trimming and release of atomic sulfur significantly improved semiconductor quality. Time-dependent XPS and first-principles calculations were used to characterize defects and their healing.
NPJ 2D MATERIALS AND APPLICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Timm Swoboda, Nicolas Wainstein, Sanchit Deshmukh, Cagil Koroglu, Xing Gao, Mario Lanza, Hans Hilgenkamp, Eric Pop, Eilam Yalon, Miguel Munoz Rojo
Summary: Heat dissipation is a major concern for electronic devices, especially at the nanoscale. Scanning thermal microscopy (SThM) is a versatile tool for measuring device temperature with nanoscale resolution but quantifying thermal features is challenging. This study calibrates a thermo-resistive SThM probe using metal lines of different widths and evaluates its sensitivity under different conditions. The results provide new insights for accurately determining the temperature of scanned devices.
Article
Materials Science, Multidisciplinary
Hon-Loen Sinn, Aravindh Kumar, Eric Pop, Akm Newaz
Summary: Researchers demonstrated a bismuth-1L-MoS2-bismuth device with ohmic electrical contacts and extraordinary optoelectronic properties by suppressing metal-induced gap states (MIGS) at the metal-monolayer MoS2 interface. This overcomes Fermi-level pinning and expands the application range of optoelectronic devices based on 2D transition metal dichalcogenides.
ADVANCED PHOTONICS RESEARCH
(2023)
