Article
Materials Science, Multidisciplinary
Suman Kalyan Maroju, Appalakondaiah Samudrala
Summary: In this study, the electronic properties of undoped and carrier-doped WS2 monolayer were systematically examined using ab initio calculations. It was found that the undoped WS2 monolayer is a semiconductor with a direct bandgap, similar to 2H-MoS2 monolayer. Additionally, significant changes were observed in the electron-doped WS2 monolayer compared to hole-doped. The dynamical stability of pristine and carrier-doped WS2 monolayer was also investigated, along with the possibility of superconducting nature in carrier-doped single-layer WS2.
PHYSICA STATUS SOLIDI-RAPID RESEARCH LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Jiaolian Luo, Yurou Zhang, Meiyan Liu, Anqi Yang, Zhenyu Xie
Summary: Based on density functional theory and the pseudo-potential plane wave method, this study investigates the feasibility of LiMn2O4 thin films in transparent devices. Co-doped LiMn2O4 was used to enhance the energy density, cycle performance, and optical properties of the films. The computational results contribute to an in-depth understanding of LiMn2O4 materials and provide insights for designing innovative experiments in the field of battery and optical transparency applications.
MATERIALS TODAY COMMUNICATIONS
(2023)
Article
Chemistry, Physical
Asad Mahmood, Guanhong Lu, Xiao Wang, Yan Wang, Xiaofeng Xie, Jing Sun
Summary: Using first principles calculation, this study explores the role of induced defects in 2D WS2/MoS2 van der Waals heterostructures, showing that defects can alter the electronic structure and improve photocatalytic properties, as well as enhance the oxygen evolution reaction.
JOURNAL OF POWER SOURCES
(2022)
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
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
Chemistry, Multidisciplinary
Chen Chong, Hongxia Liu, Shulong Wang, Kun Yang
Summary: This study investigated the electronic structure properties of single-layer MoS2 crystals under biaxial strain using density functional theory. Results showed a transition from direct to indirect band gap with small strain, maintaining characteristics of indirect band gap with increasing strain and linear decrease in band gap. Further analysis of density of states, sub-orbital density of states, thermodynamic parameters, and Raman spectroscopy revealed the strain-induced variations in single-layer MoS2, providing a theoretical basis for strain regulation of MoS2.
Article
Chemistry, Physical
P. Sundara Venkatesh, N. Kannan, M. Ganesh Babu, G. Paulraj, K. Jeganathan
Summary: This study explores the effect of transition metal doping on 2D MoS2 nanosheets for the electrocatalytic hydrogen evolution reaction (HER). High-quality MoS2 nanosheets with randomly doped metal ions were synthesized using a hydrothermal method. It was found that Ni-MoS2 exhibited superior HER performance compared to Co-MoS2 and Fe-MoS2.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2022)
Article
Electrochemistry
Shouheng Li, Zheng Luo, Shanshan Wang, Haifeng Cheng
Summary: This review comprehensively summarizes the research progress on doping strategies of MoS2 to enhance its catalytic activity, and provides a deep understanding of the structure-activity relationship for catalyst design.
ELECTROCHEMISTRY COMMUNICATIONS
(2023)
Article
Nanoscience & Nanotechnology
Jiawei Li, Na Li, Qinqin Wang, Zheng Wei, Congli He, Dashan Shang, Yutuo Guo, Woyu Zhang, Jian Tang, Jieying Liu, Shuopei Wang, Wei Yang, Rong Yang, Dongxia Shi, Guangyu Zhang
Summary: The development of stretchable 2D semiconductor devices has significant applications. This study successfully fabricated stretchable MoS2 FETs with excellent performance and stability, and demonstrated their potential in applications such as optoelectronic synapse and neural network simulations.
ADVANCED ELECTRONIC MATERIALS
(2022)
Article
Nanoscience & Nanotechnology
Tian Carey, Adrees Arbab, Luca Anzi, Helen Bristow, Fei Hui, Sivasambu Bohm, Gwenhivir Wyatt-Moon, Andrew Flewitt, Andrew Wadsworth, Nicola Gasparini, Jong M. Kim, Mario Lanza, Iain McCulloch, Roman Sordan, Felice Torrisi
Summary: The authors demonstrate air-stable, low voltage operation of inkjet-printed MoS2 and IDT-BT FETs, achieving complementary logic inverters with promising application prospects.
ADVANCED ELECTRONIC MATERIALS
(2021)
Article
Multidisciplinary Sciences
Alex M. Ganose, Junsoo Park, Alireza Faghaninia, Rachel Woods-Robinson, Kristin A. Persson, Anubhav Jain
Summary: The authors developed a computationally efficient method for calculating carrier scattering rates of semiconductors, which shows similar accuracy to state-of-the-art methods but at a much lower computational cost. This approach enables high-throughput computational workflows for accurate screening of carrier mobilities, lifetimes, and thermoelectric power.
NATURE COMMUNICATIONS
(2021)
Article
Chemistry, Multidisciplinary
Lidia Kuo, Vinod K. Sangwan, Sonal Rangnekar, Ting-Ching Chu, David Lam, Zhehao Zhu, Lee J. Richter, Ruipeng Li, Beata M. Szydlowska, Julia R. Downing, Benjamin J. Luijten, Lincoln J. Lauhon, Mark C. Hersam
Summary: Aerosol-jet printing technology is utilized to achieve highly responsive photodetectors with superior optoelectronic properties, surpassing previously reported devices by three orders of magnitude. Properly designed processing and ink formulations enable the processing and application of ultrathin MoS2 nanosheets, providing a new approach for scalable manufacturing in mechanically flexible optoelectronics.
ADVANCED MATERIALS
(2022)
Article
Chemistry, Physical
Yuanlyu Mao, Yuqiang Fang, Kaidi Yuan, Fuqiang Huang
Summary: In this study, V-doped MoS2 material was successfully synthesized and the influence of V doping on its thermoelectric properties was investigated. V doping significantly enhanced the electrical conductivity and thermoelectric performance of MoS2, and introduced lattice defects and grain refinement effects. In addition, VxMo1-xS2 showed obvious anisotropy in transport properties.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Chemistry, Multidisciplinary
Koosha Nassiri Nazif, Aravindh Kumar, Jiho Hong, Nayeun Lee, Raisul Islam, Connor J. McClellan, Ouri Karni, Jorik van de Groep, Tony F. Heinz, Eric Pop, Mark L. Brongersma, Krishna C. Saraswat
Summary: Layered semiconducting transition metal dichalcogenides (TMDs) have excellent optoelectronic properties, but practical contacts to TMDs have poor charge carrier selectivity, leading to low open-circuit voltage (V-OC) and limited power conversion efficiency (PCE). A simple MoOx (x approximate to 3) surface charge-transfer doping and passivation method was applied to multilayer tungsten disulfide (WS2) solar cells to address these issues, resulting in lateral p-n junction photovoltaic cells with a record V-OC of 681 mV, the highest among all p-n junction TMD solar cells with a practical design, and leading to record PCE in ultrathin (<90 nm) WS2 photovoltaics.
Article
Materials Science, Multidisciplinary
Lilin Gao, Junyan Li, Nan Gao, Shaoheng Cheng, Hongdong Li
Summary: The possible structures of substituted N and N-Six (x=1,2,3,4) complexes in diamond are investigated using first-principles calculation. The electron distribution around the N dopant in stable N-Six (x=0,1,2) structures is asymmetrical with deep donor levels. However, for the stable N-Six (x=3) structure, the N atom is tetracoordinated and there is an increased contribution of Si to the donor energy level. The formation energies and binding energies also increase with the increased Si atoms. This work provides insights into the doping features of N-Si complexes in diamond.
DIAMOND AND RELATED MATERIALS
(2023)
Article
Engineering, Electrical & Electronic
Narasimhulu Thoti, Yiming Li, Wen-Li Sung
Summary: This study investigates the WKF of strained Si0.6Ge0.4 TFET with nanosheet geometry, showing that fewer WKFs are identified with higher MGN. The average energy reduction affects electron transport, with a higher reduction observed with high MGN and a lower reduction with low MGN. The variability in V-th increases with progressively diminished MGN, and marginal variations in SS, I-ON, and I-OFF are observed due to the dependability of WKF over the subthreshold region of operation.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2022)
Article
Nanoscience & Nanotechnology
Narasimhulu Thoti, Yiming Li
Summary: This work demonstrates the effectiveness of using ferroelectricity in tunneling field-effect transistors (TFETs). By optimizing the metal-ferroelectric-semiconductor (OMFS) structure, the utilization of polarization and electric fields of the ferroelectric material Hf0.5Zr0.5O2 in the tunneling region is significantly improved. In addition, the TFET geometry and other enhancements further enhance the performance of TFETs.
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
Computer Science, Hardware & Architecture
Rajat Butola, Yiming Li, Sekhar Reddy Kola, Chandni Akbar, Min-Hui Chuang
Summary: In this study, the effects of process variations on the electrical characteristics of stacked GAA silicon NS CFETs are predicted using an LSTM-based ML model, which is less time-consuming and computationally effective compared to conventional device modeling tools.
COMPUTERS & ELECTRICAL ENGINEERING
(2023)
Article
Chemistry, Multidisciplinary
Chieh-Yang Chen, Yiming Li, Min-Hui Chuang
Summary: In this study, we investigate the electronic structures of ternary 2D materials (Mo1-xCrxS2 and W1-xCrxS2) containing transition metal chalcogenides. By controlling the mole fractions of chromium (Cr), the direct band gaps and work functions of these materials can be tuned. The presence of Cr atoms also leads to structural deformation and increased thickness of the monolayer structures.
Article
Psychology, Clinical
Yi-Chien Ku, Hung-Ping Chung, Chia-Yu Hsu, Yuan-Hao Cheng, Freya In-Chu Hsu, Yi-Chia Tsai, En Chao, Tony Szu-Hsien Lee
Summary: Deferred Prosecution with Condition to Complete the Addiction Treatment (DPCCAT) is a program in Taiwan that shifts drug users from the label of drug offenders to patients. The effectiveness of completing the DPCCAT program on drug users is not well understood. This study examined recidivism rates and time to relapse among different drug user groups in a nationwide population-based retrospective data. The results showed that completion of the DPCCAT program significantly reduced the risk of recidivism for Schedule I drug users only, but was less effective for polydrug users and heterogeneous groups. Consideration of drug user characteristics and criminal offenses is suggested when offering the DPCCAT program.
INTERNATIONAL JOURNAL OF MENTAL HEALTH AND ADDICTION
(2023)
Article
Crystallography
Tsau-Hua Hsieh, Wei-Ta Huang, Kuo-Bin Hong, Tzu-Yi Lee, Yi-Hong Bai, Yi-Hua Pai, Chang-Ching Tu, Chun-Hui Huang, Yiming Li, Hao-Chung Kuo
Summary: We compared the performance of commercial mu-LEDs and three-layered staggered QW mu-LED arrays, and investigated the self-heating effect. We proposed a green mu-RCLED with staggered MQWs and Ta2O5/SiO2 DBRs. Simulation results showed that the staggered MQWs reduced blue-shift and maintained output power at high input current, while the Ta2O5/SiO2 DBRs significantly reduced FWHM and divergence angle. The mu-RCLEDs effectively resolved wavelength instability and color purity issues of conventional mu-LEDs.
Article
Nanoscience & Nanotechnology
Narasimhulu Thoti, Yiming Li
Summary: This paper computationally studies the electrical characteristics of a complementary tunneling field effect transistor (CTFET) for the first time. The CTFET is designed with 3D vertically stacked n-TFET and p-TFET channels with gate-all-around (GAA) nanosheet SiGe options. The study shows that CTFET has high scalability and improved circuit performance, making it a potential alternative to conventional TFETs.
Article
Computer Science, Information Systems
V. Bharath Sreenivasulu, Aruna Kumari Neelam, Sekhar Reddy Kola, Jawar Singh, Yiming Li
Summary: This article demonstrates and compares the performance of 3-D nanosheet FET (NS-FET) in inversion (INV) and junctionless (JL) modes at both device and circuit levels. The JL mode NS-FETs exhibit higher ON current (I-ON) with increasing temperature, while the INV mode shows a better negative temperature coefficient of threshold voltage (dV(th)/dT). Circuit simulations using the Cadence Virtuoso platform reveal a 20% increase in gain for INV mode compared to JL mode in a common source (CS) amplifier. The results provide a better understanding of the NS-FET in advanced technology nodes.
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
Computer Science, Information Systems
Sagarika Dash, Yiming Li, Wen-Li Sung
Summary: This paper proposes a hybrid deep learning approach for predicting the electrical characteristics of multichannel devices induced by work function fluctuation (WKF) with a smaller dataset. The proposed model combines 1D-CNN and LSTM algorithms to model all four channels of GAA silicon Nanosheet and Nanofin MOSFETs. Experimental results demonstrate that the hybrid model outperforms three individual DL models in terms of prediction accuracy on a small dataset.
Article
Engineering, Electrical & Electronic
Ya-Shu Yang, Yiming Li, Sekhar Reddy Kola
Summary: We propose a compact modeling framework based on the GF model and ANNs for emerging GAA MOSFETs. The framework includes two ANNs, with the first one capturing the main trend and variation of device I-V characteristics even with limited or out-of-range training data. The second ANN further improves model accuracy by minimizing errors. Our approach achieves similar accuracy with only 20% of the training data compared to recent ML models.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Engineering, Electrical & Electronic
Wen-Li Sung, Yiming Li, Min-Hui Chuang
Summary: This article proposes grain-pattern-dependent threshold-voltage models to predict the variability of V-th due to work-function fluctuation for vertically stacked multichannel gate-all-around silicon nanosheet MOSFETs. The models were also applied to estimate the variability of static noise margin of different circuits. By statistically counting the perturbed local metal grains, the model explains the impact of metal grain location on V-th. Compared with 3-D device simulation, the model prediction has an error rate of less than 0.5%. Furthermore, an empirical expression is presented that can be easily incorporated into a circuit simulator to assess the variability of circuit performance affected by work-function fluctuation.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Engineering, Electrical & Electronic
Rajat Butola, Yiming Li, Sekhar Reddy Kola
Summary: In this work, a dynamic weighting-artificial neural network (DW-ANN) methodology is introduced for quick and automated compact model (CM) generation. It combines the accuracy of TCAD simulations and the cost-effectiveness of SPICE simulations. The methodology is applied to gate-all-around (GAA) silicon (Si) nanosheet (NS) complementary field effect transistor (CFET), which is a potential candidate for future CMOS technology. By using DW-ANN, the critical process variation (PV) sources that degrade CFET performance can be estimated with less than 1% error. Additionally, a compact DW-ANN-based Verilog-A model is developed for accurate circuit-level analysis. The overall average error of the model is reported to be less than 2%. Therefore, this proposed device and circuit modeling approach offers a feasible solution for rapidly modeling new emerging devices with good convergence and high accuracy.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Nanoscience & Nanotechnology
Yiming Li, Min-Hui Chuang, Yu-Chin Tsai
Summary: This paper computationally studies the electrical characteristics of gate-all-around fin field effect transistors (GAA FinFETs) and negative capacitance GAA FinFETs (NC-GAA FinFETs) for sub-3-nm technological nodes. It is found that NC-GAA FinFETs exhibit larger standard deviation of threshold voltage due to workfunction fluctuation. The inverter of NC-GAA FinFETs shows larger noise margin and shorter delay time compared to GAA FinFETs, but suffers from larger variability induced by workfunction fluctuation.
NANOSCALE RESEARCH LETTERS
(2022)
