Article
Chemistry, Multidisciplinary
Z. Lotfi, M. B. Gholivand, M. Shamsipur
Summary: In this study, nickel-doped molybdenum diselenide nanosheets were successfully synthesized and integrated with carboxylated multiwalled carbon nanotubes, forming a composite material. The prepared nanocomposite showed excellent catalytic performance as an electrochemical catalyst for methanol oxidation reaction. It exhibited a low onset potential and high activity, and maintained 90% of its activity even after a long duration of time. Therefore, the nickel-doped molybdenum diselenide/carboxylated multiwalled carbon nanotubes composite is a promising and cost-effective anode catalyst for methanol oxidation reaction.
MATERIALS TODAY CHEMISTRY
(2023)
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, Multidisciplinary
Melissa Li, Claudio U. Hail, Souvik Biswas, Harry A. Atwater
Summary: We demonstrate dynamic beam steering by an active van der Waals metasurface utilizing the excitonic resonances of monolayer molybdenum diselenide (MoSe2). By controlling the radiative and nonradiative rates of excitons, we can dynamically control the reflection amplitude and phase profiles, resulting in an excitonic phased array metasurface. This approach shows potential for wavefront shaping in emerging photonic applications.
Article
Nanoscience & Nanotechnology
Ziyang Wang, Fangyuan Sun, Zihan Liu, Libing Zheng, Dazheng Wang, Yanhui Feng
Summary: In this study, the effect of interfacial roughness on the thermal boundary conductance (TBC) between copper and diamond is investigated using molecular dynamics simulations and time-domain thermoreflectance experiments. It is found that a rough interface improves thermal transport efficiency and increases TBC by 5.5 times compared to a flat interface. The phonon scattering probability increases with roughness and stabilizes gradually. Experimental measurements using time-domain thermoreflectance confirm the results of the simulations. This study provides a theoretical and experimental basis for roughness modification in interfacial thermal management and suggests a new approach for enhancing the thermal conductivity of composites.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Nanoscience & Nanotechnology
Won Tae Kang, Thanh Luan Phan, Kyung Jin Ahn, Ilmin Lee, Young Rae Kim, Ui Yeon Won, Ji Eun Kim, Young Hee Lee, Woo Jong Yu
Summary: This study demonstrates direct growth of MoSe2 films on selective pattern areas via a surface-mediated liquid-phase promoter using a solution-based approach, resulting in highly uniform films and the ability to produce other TMD films. The approach also allows control over various pattern shapes, sizes, and large-scale areas, improving applicability in future devices. The patterned MoSe2 field-effect transistor device exhibits a p-type dominant conduction behavior with a high on/off current ratio, providing guidance for future design of integrated devices for large-scale application.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Nanoscience & Nanotechnology
Heungdong Kwon, Christopher Perez, Woosung Park, Mehdi Asheghi, Kenneth E. Goodson
Summary: The study introduced metal nanograting structures as opto-thermal transducers in TDTR to measure the TBC of metal-oxide interfaces, demonstrating improved measurement sensitivity.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Materials Science, Multidisciplinary
Xiaoyan Liu, Fangyuan Sun, Wei Wang, Jie Zhao, Luhua Wang, Zhanxun Che, Guangzhu Bai, Xitao Wang, Jinguo Wang, Moon J. Kim, Hailong Zhang
Summary: The thermal conductivity of a diamond particle reinforced copper matrix composite is significantly influenced by the non-wetting heterointerface. This study investigates the effect of a chromium (Cr) interlayer on the interface thermal conductance between copper and diamond. The results show that the addition of a Cr interlayer enhances the interfacial adhesion and improves the thermal conductance between copper and diamond.
INTERNATIONAL JOURNAL OF MINERALS METALLURGY AND MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Yang Wang, David W. Collinson, Heungdong Kwon, Robert D. Miller, Krystelle Lionti, Kenneth E. Goodson, Reinhold H. Dauskardt
Summary: Thermal transport in polymer nanocomposites is influenced by the interfacial thermal conductance, which is determined by the density of internal interfaces. However, there is a lack of experimental measurements linking thermal conductance to the chemistry and bonding between polymer molecules and the glass surface. To address this issue, polymers are confined in porous organosilicates with high interfacial densities. The thermal conductivities of the composites are measured using time-domain thermoreflectance, and the thermal boundary conductance is extracted using effective medium theory and finite element analysis. This analysis platform provides a new paradigm for studying heat flow across different domains.
Article
Nanoscience & Nanotechnology
Hai Yen Le Thi, Muhammad Atif Khan, A. Venkatesan, Kenji Watanabe, Takashi Taniguchi, Gil-Ho Kim
Summary: This study demonstrates the advantage of integrating 1D indium metal contact with MoS2 fully encapsulated within hexagonal boron nitride, showing high-quality electrical performance and analyzing the charge-transport mechanism in detail. The results are promising for using air-sensitive material heterostructures and designing trending flexible, transparent electronic wearable devices at a large scale.
Article
Nanoscience & Nanotechnology
Zhun-Yong Ong, Yongqing Cai, Gang Zhang, Yong-Wei Zhang
Summary: Understanding the physical processes involved in interfacial heat transfer is crucial for interpreting thermometric measurements and optimizing heat dissipation in nanoelectronic devices based on TMD semiconductors. A phenomenological theory for modeling diffuse phonon transport at disordered interfaces was introduced in this study, with results suggesting that heat dissipation at the TMD-SiO2 interface is dominated by phonons scattered diffusely by the rough interface. Moreover, the electronic TBC contribution may also be significant even at low electron densities, potentially explaining variations in experimental TBC data.
Article
Materials Science, Multidisciplinary
Frank Angeles, Qiyang Sun, Victor H. Ortiz, Jing Shi, Chen Li, Richard B. Wilson
Summary: Interfaces play a crucial role in governing the thermal performance of nanoscale devices and nanostructured materials. Research has shown that the thermal boundary conductance between different materials ranges from 50 to 300 MW m(-2) K-1, with variations at different temperatures. This knowledge is essential for accurately modeling the temperature response of nanoscale devices and materials.
PHYSICAL REVIEW MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Youngseo Jeon, Jihyung Seo, Jihyun Kim, Dongjoon Rhee, Myeongjin Jung, Hyesung Park, Joohoon Kang
Summary: The authors of the article presented a novel method for preparing high-quality monolayer MoSe2 films and demonstrated a wafer-scale, gate-tunable photodetector array with superior optoelectronic properties using a growth promoter-assisted growth strategy. The MoSe2 film synthesized with this method showed improved crystallinity compared to the films without the growth promoter, leading to enhanced photodetector performance. The resulting photodetector array exhibited higher photoresponsivities over visible wavelengths than previously reported devices based on CVD-synthesized monolayer TMDs.
ADVANCED OPTICAL MATERIALS
(2022)
Article
Nanoscience & Nanotechnology
Jingjing Shi, Chao Yuan, Hsien-Lien Huang, Jared Johnson, Chris Chae, Shangkun Wang, Riley Hanus, Samuel Kim, Zhe Cheng, Jinwoo Hwang, Samuel Graham
Summary: This study investigates thermal transport at beta-Ga2O3/metal interfaces using theoretical modeling and experimental measurements. It highlights the significant impact of metal cutoff frequency on thermal boundary conductance, followed by chemical reactions and defects. Different metals show varying effects on the thermal boundary conductance in these interfaces.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Nanoscience & Nanotechnology
Heungdong Kwon, Christopher Perez, Hyojin K. Kim, Mehdi Asheghi, Woosung Park, Kenneth E. Goodson
Summary: By engineering two differing bonding characters through PEALD, this study demonstrates the reduction of thermal boundary resistances in nanostructured systems. Treatments using O-2 plasma and O-2 + H-2 plasma have shown different effects on thermal resistance, potentially due to the generation of stronger covalent bonds and the removal of contaminants from the PEALD Pt films. Further improvements in thermal conductivity could be achieved through thinner nucleation layers.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Chemistry, Physical
Stefan Wert, Christian Iffelsberger, Katarina A. Novcic, Martin Pumera
Summary: Transition metal dichalcogenides (TMDs) have emerged as promising materials for electrocatalysis, especially for the hydrogen evolution reaction (HER). In this study, the morphological and (electro)chemical changes of synthetic bulk crystals of MoS2, TiS2, and TiSe2 during HER were investigated. The results showed different degrees of corrosion in these materials, with TiSe2 > TiS2 > MoS2.
JOURNAL OF CATALYSIS
(2022)
Review
Chemistry, Multidisciplinary
Wonhee Ko, Zheng Gai, Alexander A. Puretzky, Liangbo Liang, Tom Berlijn, Jordan A. Hachtel, Kai Xiao, Panchapakesan Ganesh, Mina Yoon, An-Ping Li
Summary: This article reviews the recent progress in understanding the role of heterogeneities in quantum materials and their effects on quantum behaviors. The authors assess three interconnected areas, including revealing the degrees of freedom of heterogeneities, understanding their impact on quantum states, and controlling heterogeneities for new quantum functions.
ADVANCED MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Kai Wang, Lizhi Zhang, Giang D. Nguyen, Xiahan Sang, Chenze Liu, Yiling Yu, Wonhee Ko, Raymond R. Unocic, Alexander A. Puretzky, Christopher M. Rouleau, David B. Geohegan, Lei Fu, Gerd Duscher, An-Ping Li, Mina Yoon, Kai Xiao
Summary: Defects are common in 2D materials and can greatly influence their properties. The authors have developed a method using Au-assisted chemical vapor deposition to selectively form antisite defects in WS2 monolayers. Experimental and theoretical analyses confirm the effectiveness of this bottom-up synthesis approach, with potential applications in the synthesis of other 2D materials.
ADVANCED MATERIALS
(2022)
Article
Polymer Science
Dong Zhou, Miguel Fuentes-Cabrera, Akash Singh, Raymond R. Unocic, Jan Michael Y. Carrillo, Kai Xiao, Yumeng Li, Bo Li
Summary: In this study, the interaction between atomic edges and polyethylene chains was investigated using advanced synthesis and molecular simulations. It was discovered that Mo-ZZ edges act as preferred nucleation sites and strongly interact with HDPE chains. The atomic structure of MoSe2 was found to influence its interactions with HDPE chains.
Biographical-Item
Engineering, Electrical & Electronic
Martin Dawson, D. B. Geohegan, T. M. Spinka, C. Jagadish
PROGRESS IN QUANTUM ELECTRONICS
(2022)
Article
Chemistry, Multidisciplinary
Ting Zheng, Yu-Chuan Lin, Neema Rafizadeh, David B. Geohegan, Zhenhua Ni, Kai Xiao, Hui Zhao
Summary: The charge transfer properties of van der Waals heterostructures formed by Janus and regular transition metal dichalcogenide monolayers have been studied. It is found that the charge transfer from regular to Janus monolayers is ultrafast, regardless of the direction of the Janus field. However, the charge transfer from Janus to regular layers is directional and controlled by the Janus field. The transferred carriers form interlayer excitons with extended lifetimes compared to intralayer excitons. These findings indicate that Janus structures can be utilized to create 2D heterostructures with efficient and directional charge transfer properties.
Article
Chemistry, Multidisciplinary
Qingkai Qian, Wenjing Wu, Lintao Peng, Yuanxi Wang, Anne Marie Z. Tan, Liangbo Liang, Saban M. Hus, Ke Wang, Tanushree H. Choudhury, Joan M. Redwing, Alexander A. Puretzky, David B. Geohegan, Richard G. Hennig, Xuedan Ma, Shengxi Huang
Summary: The electronic and optical properties of two-dimensional materials can be altered by defects. In this study, defects created by remote plasma exposure in single-layer WS2 induce a distinct low-energy photoluminescence peak at 1.59 eV. This peak is caused by sulfur substitutions by nitrogen.
Article
Chemistry, Multidisciplinary
Ningxin Li, Aisha Okmi, Tara Jabegu, Hongkui Zheng, Kuangcai Chen, Alexander Lomashvili, Westley Williams, Diren Maraba, Ivan Kravchenko, Kai Xiao, Kai He, Sidong Lei
Summary: Biomimetic artificial vision is gaining attention, especially in the development of neuromorphic electronic devices, artificial intelligence, and microrobotics. However, the current research lacks color recognition, the most critical vision function, due to the downsizing challenges of existing color sensing devices. In this study, we present a van der Waals semiconductor-enabled vertical color sensing structure that focuses on compact device profile and accurate color recognition capability. Additionally, we introduce chromatic aberration correction to the color sensor hardware, simplifying the design of optical lens systems and further reducing the size of artificial vision systems. The scalability and practical potentials of our developed device architecture are demonstrated by a multiple pixel prototype device in this research.
Article
Chemistry, Multidisciplinary
Yiyi Gu, Lizhi Zhang, Hui Cai, Liangbo Liang, Chenze Liu, Anna Hoffman, Yiling Yu, Austin Houston, Alexander A. Puretzky, Gerd Duscher, Philip D. Rack, Christopher M. Rouleau, Xiangmin Meng, Mina Yoon, David B. Geohegan, Kai Xiao
Summary: This study reports an ambient-pressure chemical vapor deposition approach to synthesize metastable monoclinic PdSe2. Monoclinic PdSe2 is selectively synthesized under S-deficient conditions, and its structure and properties are characterized by first-principles calculations and experimental techniques. Monoclinic PdSe2 exhibits strong optical anisotropy and high electron mobility, which is of significant importance for the synthesis of other 2D transition metal dichalcogenides.
Article
Chemistry, Multidisciplinary
Sumner B. Harris, Yu-Chuan Lin, Alexander A. Puretzky, Liangbo Liang, Ondrej Dyck, Tom Berlijn, Gyula Eres, Christopher M. Rouleau, Kai Xiao, David B. Geohegan
Summary: In this study, a feedback approach was used to investigate the transformation pathways of monolayer WS2 crystals into Janus WSSe and WSe2. Real-time Raman spectroscopy and photoluminescence were employed to assess the structure, composition, and optoelectronic quality of the monolayer crystal during the implantation of selenium. The results provide a method to achieve fractional and complete Janus WSSe monolayers as metastable transition states.
Editorial Material
Chemistry, Physical
David B. Geohegan, Alexander A. Puretzky, Kai Xiao
Summary: An alloy engineering approach has been developed to grow atomically thin bilayers with predictable and tunable moire patterns reliably.
Article
Multidisciplinary Sciences
Marti Checa, Addis S. Fuhr, Changhyo Sun, Rama Vasudevan, Maxim Ziatdinov, Ilia Ivanov, Seok Joon Yun, Kai Xiao, Alp Sehirlioglu, Yunseok Kim, Pankaj Sharma, Kyle P. Kelley, Neus Domingo, Stephen Jesse, Liam Collins
Summary: Unraveling local dynamic charge processes is essential for progress in various fields. Researchers have developed high-speed sparse scanning Kelvin probe force microscopy, enabling sub-second imaging of nanoscale charge dynamics and enhancing understanding of material heterogeneities.
NATURE COMMUNICATIONS
(2023)
Article
Chemistry, Physical
Weijun Luo, Akinola D. Oyedele, Nannan Mao, Alexander Puretzky, Kai Xiao, Liangbo Liang, Xi Ling
Summary: This study investigates the resonance enhancement effect in PdSe2 using angle-resolved polarized Raman spectroscopy, and finds that the Raman intensities of the breathing mode B1 and A(g)(1) mode are the strongest when the incident polarization is parallel to the a axis of PdSe2. By controlling the excitation energy within the range of 2.18 to 2.38 eV, the strongest intensities of B1, A(g)(1), and A(g)(3) modes can be achieved, which is attributed to the resonance enhancement caused by absorption.
ACS PHYSICAL CHEMISTRY AU
(2022)
