Article
Nanoscience & Nanotechnology
Mingxiang Zhang, Shiyin Zhao, Zhicheng Zhao, Shun Li, Fei Wang
Summary: Piezoelectric catalysis using Ni-decorated GaN nanowires has been shown to enhance hydrogen generation by 9 times compared to Pt-loaded GaN nanowires under ultrasonic vibration, with superior efficiency observed in Ni/GaN nanowires with smaller diameters. The results demonstrate the potential application of non-noble metal loaded GaN nanostructures in hydrogen generation driven by weak mechanical energy.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Chemistry, Physical
Qingyuan Luo, Ronghuo Yuan, Yan-Ling Hu, Defa Wang
Summary: InxGa1-xN nanowires with core/shell structure grown on n-type Si substrate by Ni-assisted CVD method were studied for their photocatalytic properties. Thicker GaN shell was found to reduce photoactivity, and a strategy to improve performance was proposed.
APPLIED SURFACE SCIENCE
(2021)
Article
Materials Science, Multidisciplinary
Kun Ye, Bochong Wang, Anmin Nie, Kun Zhai, Fusheng Wen, Congpu Mu, Zhisheng Zhao, Jianyong Xiang, Yongjun Tian, Zhongyuan Liu
Summary: The high crystallinity one-dimensional Sb2S3 nanowires were grown on SiO2/Si substrates via CVD technique, showing excellent photodetection properties with a broad photoresponse range and outstanding performance indicators, as well as remarkable switch cycling stability.
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
(2021)
Article
Physics, Applied
Caroline E. Reilly, Nirupam Hatui, Thomas E. Mates, Shuji Nakamura, Steven P. DenBaars, Stacia Keller
Summary: This research explores the growth of AlN at temperatures below 550 degrees C via MOCVD using a flow-modulated epitaxy scheme, investigating the morphological, compositional, and electronic properties of the films. The study reveals high sheet charges and mobilities for two dimensional electron gases formed at the interface between the low temperature grown AlN layers and the high temperature deposited semi-insulating GaN base layers. Despite low growth temperatures, unintentional gallium incorporation is observed in nominally pure AlN barrier layers near the GaN interface. These results pave the way for the integration of nitride-based electronics on temperature sensitive substrates via epitaxy-based schemes.
APPLIED PHYSICS LETTERS
(2021)
Article
Chemistry, Multidisciplinary
Karol Olszewski, Marta Sobanska, Vladimir G. Dubrovskii, Egor D. Leshchenko, Aleksandra Wierzbicka, Zbigniew R. Zytkiewicz
Summary: This study focused on the growth of GaN nanowires on Si(111) substrates using plasma-assisted molecular beam epitaxy, specifically investigating the orientation and growth rate of the nanowires. The researchers found that vertically aligned nanowires grew faster and produced more regular ensembles compared to inclined nanowires. These densely packed ensembles of vertically aligned GaN nanowires on ZrN/Si(111) surfaces are highly relevant for device applications.
Article
Chemistry, Physical
Wenhao Ding, Xianquan Meng
Summary: Gallium nitride nanowires and beta-Ga2O3 nanowires were prepared using chemical vapor deposition to fabricate a solar-blind ultraviolet detector. The detector shows excellent response to deep ultraviolet light with high detectivity and stability, making it a promising device for UV detection applications.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Chemistry, Physical
Muhammad Ali Ehsan, Abuzar Khan, Muhammad Nadeem Zafar, Usman Ali Akber, Abbas Saeed Hakeem, Muhammad Faizan Nazar
Summary: In recent years, nickel sulfide impregnated electrocatalysts with auxiliary structural features have been developed as effective alternatives for oxygen evolution reaction (OER) in alkaline medium. Nickel sulfide (NiS) nanowire electrodes grown directly on nickel foam (NF) demonstrated excellent OER activity in 1.0 M KOH solution, with low Tafel value and good stability. The surface of the NiS catalyst was partially modified into nickel oxide after electrolysis, leading to enhanced water oxidation performance.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2022)
Article
Materials Science, Multidisciplinary
Min Joo Ahn, Kyu-yeon Shim, Woo Seop Jeong, Seongho Kang, Hwayoung Kim, Dae-sik Kim, Junggeun Jhin, Jaekyun Kim, Dongjin Byun
Summary: In this study, a polished plateau-patterned sapphire substrate (PP-PSS) was developed for the epitaxial growth of stress-free GaN microrods. By adjusting the polishing time, selective growth of GaN microrods was achieved on the plateau region of the substrate. The growth mechanism and crystal structure of the GaN microrods were characterized, confirming the feasibility of stress-free epitaxial growth on PP-PSS.
Article
Chemistry, Multidisciplinary
Cai Zhang, Xin Jin, Yan Liang, Liu Yang, Jing Li, Rui Wang, Baodan Liu, Xuewei Lv, Xin Jiang
Summary: This study demonstrates the growth of homogeneous and well-aligned [0001]-oriented 1-D GaN nanoarrays through a modified hydride vapor phase epitaxy (HVPE) process. The technique allows for easy control of nanowire density and length, providing Cl-rich growth conditions that result in unique morphology and optical properties of the GaN nanoarrays. The as-synthesized GaN nanoarrays exhibit a hollow bamboo-like structure and show strong visible luminescence, centered at 450 nm with the disappearance of an intrinsic emission peak.
Article
Engineering, Electrical & Electronic
Lianqing Yu, Yankun Wang, Jinhui Wang, Xingyu Zhao, Wei Xing, Liana Alvares Rodrigues, D. Amaranatha Reddy, Yaping Zhang, Haifeng Zhu
Summary: Efficient copper phthalocyanine gas sensors with sensitive and selective analysis capabilities for toxic gases at room temperature have shown great potential in recent years. In this study, a gas sensor based on copper phthalocyanine (CuPc) was prepared using a low-temperature physical vapor deposition (PVD) method. The uniform cotton-wool nanowires film had high yield and easy peel-off properties. The PVD preparation temperature significantly affected the recovery and cyclic properties of the gas sensor for chlorine. The high-performance CuPc nanowires prepared at 230 degrees C had the lowest detection limit and a much faster recovery time compared to previous results. Additionally, it exhibited excellent light-induced gas-sensitive characteristics to Cl-2 at room temperature. This sensor has potential applications in photo-gas sensors, photocatalytic devices, or photoelectric devices.
SENSORS AND ACTUATORS A-PHYSICAL
(2022)
Article
Physics, Applied
Johanna Meier, Patrick Haeuser, Christian Blumberg, Tim Smola, Werner Prost, Nils Weimann, Gerd Bacher
Summary: Site- and polarity-controlled core-shell InGaN/GaN nanorod LED structures were grown on Si(111) using metal organic vapor phase epitaxy. Uniform multiple quantum wells on polarization-free sidewalls were observed through scanning transmission electron microscope images. Spatially resolved photoluminescence mapping confirmed the emission at 3.0 eV from the polarization-free m-plane, with a fast recombination lifetime of about 490 ps at low temperatures. Quasi-resonant laser excitation demonstrated predominant radiative recombination at low excitation densities, while efficiency was decreased by Auger recombination and/or carrier leakage at high excitation densities.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Engineering, Electrical & Electronic
Guofeng Yang, Yu Ding, Naiyan Lu, Feng Xie, Yan Gu, Bingjie Ye, Yufei Yao, Xiumei Zhang, Xinxia Huo
Summary: 2D MoS2 was grown on AlGaN(GaN) substrates by CVD, forming 2D-3D MoS2-AlGaN(GaN) heterostructures. MoS2 crystals on AlGaN surface exhibit mixed and irregular shapes, while single-layer triangular MoS2 is mainly prepared on GaN surface. Both heterostructures exhibit indirect band gaps and broad-band light absorption performances.
IEEE PHOTONICS JOURNAL
(2021)
Article
Chemistry, Applied
Jia Wu, Zhixiang Zhai, Tianqi Yu, Xizi Wu, Shuaiqin Huang, Wenqing Cao, Yixuan Jiang, Jinge Pei, Shibin Yin
Summary: This study investigates the adsorption behavior and catalytic process in the 5-hydroxymethylfurfural electrooxidation reaction (HMFOR). By tuning the selective adsorption sites of NiMoO with Ni particles, the synergy between Ni and NiMoO improves the reaction kinetics and product selectivity. The coupled two-electrode system demonstrates high efficiency in converting HMF to value-added chemicals and producing pure hydrogen.
JOURNAL OF ENERGY CHEMISTRY
(2023)
Article
Nanoscience & Nanotechnology
Rui Zhang, Qiusong Zhang, Xinyu Jia, Shaofeng Wen, Haolun Wu, Yimin Gong, Yi Yin, Changyong Lan, Chun Li
Summary: In this work, a low-temperature synthesis method for large-area polycrystalline PdSe2 films on silicon substrate was presented, and their charge carrier transport behaviors were investigated. The results showed that the film thickness has a significant impact on the device performance, with thinner films exhibiting a record high on/off ratio and thicker films exhibiting the highest reported hole mobility for polycrystalline films.
Article
Materials Science, Multidisciplinary
Jia Lin, Hua Jin, Xiaohong Ge, Yihang Yang, Guimei Huang, Jinhuo Wang, Fenqiang Li, Hui Li, Shuai Wang
Summary: The study investigated the effects of synthesis temperature, time, and catalyst amount on the quality and quantity of grown CNTs. The optimal conditions for obtaining uniform size CNTs with high graphitization degree on ZrB2 were determined.
DIAMOND AND RELATED MATERIALS
(2021)
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
Nanoscience & Nanotechnology
Myeongok Kim, Maxime Giteau, Nazmul Ahsan, Naoya Miyashita, Logu Thirumalaisamy, Chen Chen, Joan M. Redwing, Yoshitaka Okada
Summary: In this paper, the growth mechanism of MoS2 films co-deposited by using a sulfur hot-lip cell and a molybdenum sputtering target via reactive sputtering was investigated. It was found that the growth is dominated by vertically-oriented sheets with horizontal branches, resulting in a tree-like structure. The anisotropic incorporation of adatoms with regards to the orientation of MoS2 is responsible for the growth front of the structures.
Article
Materials Science, Multidisciplinary
Sora Lee, Xiaotian Zhang, Thomas McKnight, Bhavesh Ramkorun, Huaiyu Wang, Venkatraman Gopalan, Joan M. Redwing, Thomas N. Jackson
Summary: This study demonstrates low-temperature processed transistors compatible with the back-end-of-the-line, which provides a new approach for improving energy efficiency and chip performance.
Article
Chemistry, Multidisciplinary
Akhil Dodda, Darsith Jayachandran, Shiva Subbulakshmi Radhakrishnan, Andrew Pannone, Yikai Zhang, Nicholas Trainor, Joan M. Redwing, Saptarshi Das
Summary: Natural intelligence is tied to learning and behavioral changes, with vision playing a critical role. Mimicking biological mechanisms can accelerate the development of AI. The study demonstrates a bioinspired machine vision system that enables dynamic learning and relearning with minimal energy expenditure.
Article
Physics, Applied
Yiwen Song, Chi Zhang, James Spencer Lundh, Hsien-Lien Huang, Yue Zheng, Yingying Zhang, Mingyo Park, Timothy Mirabito, Rossiny Beaucejour, Chris Chae, Nathaniel McIlwaine, Giovanni Esteves, Thomas E. Beechem, Craig Moe, Rytis Dargis, Jeremy Jones, Jacob H. Leach, Robert M. Lavelle, David W. Snyder, Jon-Paul Maria, Roy H. Olsson, Joan M. Redwing, Azadeh Ansari, Jinwoo Hwang, Xiaojia Wang, Brian M. Foley, Susan E. Trolier-McKinstry, Sukwon Choi
Summary: AlN thin films have great potential for applications in optoelectronics, power electronics, and microelectromechanical systems. The thermal conductivity of these thin films exhibits an anisotropic behavior, which is influenced by film thickness and grain size. Electron microscopy reveals that the presence of grain boundaries and dislocations limits the thermal conductivity. Simulation results indicate that self-heating in AlN thin films significantly affects the power handling capability of RF filters.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Chemistry, Multidisciplinary
Anushka Bansal, Nadire Nayir, Ke Wang, Patrick Rondomanski, Shruti Subramanian, Shalini Kumari, Joshua A. Robinson, Adri C. T. van Duin, Joan M. Redwing
Summary: Ultrathin 2D-GaNx can be formed by Ga intercalation into epitaxial graphene followed by nitridation. The influence of graphene layer thickness and chemical functionalization on Ga intercalation and 2D-GaNx formation is examined using experimental and theoretical studies.
Article
Chemistry, Physical
Benjamin Huet, Saiphaneendra Bachu, Nasim Alem, David W. Snyder, Joan M. Redwing
Summary: The scalable synthesis of van der Waals vertical heterostructures is important for the fabrication of novel 2D-based functional applications. Combining graphene with transition metal dichalcogenides shows potential for exploring new device architectures with unique functionalities. Experimental results reveal how the properties of the graphene template influence the growth of tungsten selenide, such as nucleation site density, growth rate, orientation, and thickness.
Article
Engineering, Electrical & Electronic
Timothy Mirabito, Ke Wang, Joan M. Redwing
Summary: The effects of pre-metallization on film stress and structural properties of undoped and Ge-doped AlxGa1-xN epilayers were investigated on AlN/sapphire templates. Pre-metallization induced a tensile growth stress in the AlxGa1-xN and improved the surface morphology, but also led to the deposition of a carbon-rich layer and increased density of screw-type dislocations. However, by adjusting the AlxGa1-xN growth rate during pre-metallization, the carbon interfacial layer could be eliminated and low surface v-pitting and threading dislocation density in Ge-doped AlxGa1-xN could be maintained.
JOURNAL OF ELECTRONIC MATERIALS
(2023)
Article
Nanoscience & Nanotechnology
Shayani Parida, Yongqiang Wang, Huan Zhao, Han Htoon, Theresa Marie Kucinski, Mikhail Chubarov, Tanushree Choudhury, Joan Marie Redwing, Avinash Dongare, Michael Thompson Pettes
Summary: Atomically thin transition metal dichalcogenides (TMDs), such as MoS2, are unique materials for next generation opto-electronic devices. Ion irradiation can be used to control the optoelectronic properties of 2D materials by manipulating atomistic defects.
Article
Chemistry, Physical
Kasra Momeni, Yanzhou Ji, Nadire Nayir, Nurruzaman Sakib, Haoyue Zhu, Shiddartha Paul, Tanushree H. Choudhury, Sara Neshani, Adri C. T. van Duin, Joan M. Redwing, Long-Qing Chen
Summary: This study developed a multiscale computational framework called the CPM model for precise control over the growth of two-dimensional materials. Experimental verification confirmed the reliability of this computational approach. The results showed that the computational method can guide the synthesis of large-area uniform two-dimensional materials via Metal-Organic Chemical Vapor Deposition (MOCVD), providing critical capabilities for fabricating electronic, optoelectronic, and quantum computing devices.
NPJ COMPUTATIONAL MATERIALS
(2022)
Article
Nanoscience & Nanotechnology
Thomas F. Schranghamer, Andrew Pannone, Harikrishnan Ravichandran, Sergei P. Stepanoff, Nicholas Trainor, Joan M. Redwing, Douglas E. Wolfe, Saptarshi Das
Summary: Limitations in cloud-based computing have led to a shift towards all-in-one edge devices that can independently sense, compute, and store data. Advanced defense and space applications face challenges in maintaining remote oversight, making the development of such devices crucial. In this study, the effects of high-dose gamma radiation on MoS2-based memtransistors were investigated. The findings show that these devices are not severely impacted by gamma irradiation, even without dedicated shielding or mitigation techniques. This research serves as a foundation for future application-oriented studies.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Chemistry, Physical
Nadire Nayir, Stephen Bartolucci, Tao Wang, Chen Chen, Joshua Maurer, Joan M. Redwing, Adri C. T. van Duin
Summary: Chemical vapor deposition (CVD) is used to produce high-quality MoS2 film on a silica substrate. ReaxFF simulations and DFT calculations provide an atomic insight into the coupling between surface chemistry and MoS2 growth. Experimental results indicate that hydroxyl groups on the silica surface enhance the reactivity with MoO3 and promote the nucleation and growth of MoS2. The presence of the substrate catalyzes the growth and lowers the growth temperature.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Multidisciplinary
Thomas F. Schranghamer, Najam U. Sakib, Muhtasim Ul Karim Sadaf, Shiva Subbulakshmi Radhakrishnan, Rahul Pendurthi, Ama Duffle Agyapong, Sergei P. Stepanoff, Riccardo Torsi, Chen Chen, Joan M. Redwing, Joshua A. Robinson, Douglas E. Wolfe, Suzanne E. Mohney, Saptarshi Das
Summary: This study investigates the impact of contact scaling on FET performance by examining Au contacts to monolayer MoS2 FETs with reduced channel length (LCH) and contact length (LC). The results show that when LC is scaled from 300 to 20 nm, Au contacts exhibit a reduction in the ON-current of approximately 2.5x, from 519 to 206 mu A/ mu m.
Article
Chemistry, Multidisciplinary
Saiphaneendra Bachu, Malgorzata Kowalik, Benjamin Huet, Nadire Nayir, Swarit Dwivedi, Danielle Reifsnyder Hickey, Chenhao Qian, David W. Snyder, Slava V. Rotkin, Joan M. Redwing, Adri C. T. van Duin, Nasim Alem
Summary: By combining experiments and theory, we investigated the influence of stacking order and twist angle of CVD graphene on the nucleation of WSe2 crystals. We found that interlayer dislocations are present only in Bernal-stacked bilayer graphene, not in twisted bilayer graphene. The localized buckles in Bernal-stacked graphene serve as thermodynamically favorable sites for binding WSe x molecules, resulting in a higher nucleation density of WSe2.
Article
Chemistry, Multidisciplinary
Raj Kumar, Cristian V. Ciobanu, Somilkumar J. Rathi, Joseph E. Brom, Joan M. Redwing, Frank Hunte
Summary: This study reports on the manifestations of superconducting electrons carried by topological surface states (TSS) in Bi2Se3 films. By measuring the magnetoresistance (MR) and anisotropic magnetoresistance (AMR), key features of TSS-carried Cooper pairs are uncovered. These findings can guide novel developments in superconductor/topological insulator quantum devices relying on supercurrent detection and lead to more refined transport signatures of Majorana zero-modes in the future.
