A5062513708- 2D Materials and Applications
- MXene and MAX Phase Materials
- Graphene research and applications
- Ferroelectric and Negative Capacitance Devices
- Chalcogenide Semiconductor Thin Films
- Organic Electronics and Photovoltaics
- Advanced Memory and Neural Computing
- Perovskite Materials and Applications
- Molecular Junctions and Nanostructures
- Ferroelectric and Piezoelectric Materials
- Nanowire Synthesis and Applications
- Solid-state spectroscopy and crystallography
- Heusler alloys: electronic and magnetic properties
- Gas Sensing Nanomaterials and Sensors
- Surface Chemistry and Catalysis
- Advanced Photocatalysis Techniques
- Advanced biosensing and bioanalysis techniques
- Semiconductor materials and interfaces
- Organic and Molecular Conductors Research
- Force Microscopy Techniques and Applications
- Electron and X-Ray Spectroscopy Techniques
- Advanced Electron Microscopy Techniques and Applications
- Block Copolymer Self-Assembly
- Recycling and Waste Management Techniques
- Semiconductor materials and devices
University of Nebraska–Lincoln
2018-2024
Abstract 2D carbides and nitrides (MXenes) are widely recognized for their exceptional promise numerous applications. However, physical property measurements of individual monolayers remain very limited despite importance revealing the intrinsic properties MXenes. The first mechanical electrical single‐layer flakes Nb 4 C 3 T x MXene, which prepared via an improved synthetic method reported. Characterization field‐effect transistor devices based on shows conductivity 1024 ± 165 S cm −1 , is...
Quasi-one-dimensional (quasi-1D) materials enjoy growing interest due to their unusual physical properties and promise for miniature electronic devices. However, the mechanical exfoliation of quasi-1D into thin flakes nanoribbons received considerably less attention from researchers than conventional layered crystals. In this study, we investigated micromechanical representative crystals, TiS3 whiskers, demonstrate that they typically split narrow with very smooth, straight edges clear...
MXenes, two-dimensional transition metal carbides or nitrides, have recently shown great promise for gas sensing applications. We demonstrate that the sensitivity of intrinsically metallic Ti3C2Tx MXene can be considerably improved via its partial oxidation in air at 350 °C. The annealed films sheets remain electrically conductive, while their decoration with semiconducting TiO2 improves chemiresistive response to organic analytes low-ppm concentrations dry air, which was used emulate...
MXenes are an emerging family of transition-metal carbides, nitrides, and carbonitrides that promising for a variety applications, including energy storage, gas sensors, electromagnetic interference shielding. A recent report on very high breakdown current density ∼1.2 × 108 cm–2 in Ti3C2Tx further extended the list potential applications to miniaturized on-chip interconnects. In this study, we investigated another member MXene family, Nb4C3Tx, found it also has ∼1.1 cm–2, which is...
We propose a strategy for highly tunable gas sensors, in which MXene is combined with sacrificial material that could be controllably oxidized upon mild annealing to form oxide nanoparticles alter the sensing response. A controlled of such composite generally retains integrity sheets while gradually converting metal semiconductor heterojunctions MXene, fine-tuning its sensor properties. This demonstrated using sensors based on Ti3C2Tx mixed TiS3, semiconducting transition trichalcogenide....
The interfaces of layered trichalcogenide TiS3(001), with metals Au and Pt, were examined using X-ray photoemission spectroscopy. In spite the fact that both Pt are large work function metals, no evidence Schottky barrier formation was found this n-type semiconductor. Two- four-terminal field-effect transistor measurements performed on exfoliated few-nm-thick TiS3 crystals pure contacts indicate forms an Ohmic contact negligible resistance. absence appreciable is attributed to strong...
Strain engineering is a powerful strategy to control the physical properties of material-enabling devices with enhanced functionality and improved performance. Here, we investigate modulation transport behavior two-dimensional MoS2 junctions under mechanical stress induced by tip an atomic force microscope (AFM). We show that junction resistance can be reversibly tuned up 4 orders magnitude altering tip-induced force. Analysis stress-induced evolution I-V characteristics indicates combined...
Scalable fabrication of graphene nanoribbons with narrow band gaps has been a nontrivial challenge. Here, we have developed simple approach to access using hybrid edge structures. Bottom-up liquid-phase synthesis bent N = 6/8 armchair (AGNRs) achieved in high efficiency through copolymerization between an o-terphenyl monomer and naphthalene-based monomer, followed by Scholl oxidation. An unexpected 1,2-aryl migration discovered, which is responsible for introducing kinked structures into the...
Abstract One of the exceptional features van der Waals (vdW) ferroelectrics is existence stable polarization at a level atomically thin monolayers. This ability to withstand detrimental effect depolarization fields gives rise complex domain configurations characterized, among others, by presence layered “antipolar” head‐to‐head (H‐H) or tail‐to‐tail (T‐T) dipole arrangements. In this study, tomographic piezoresponse force microscopy (TPFM) employed study 3D arrangement in vdW ferroelectric...
We demonstrate that decoration with methylammonium lead iodide perovskite (MAPbI3) nanoparticles is an efficient approach to engineer strong visible light photoresponse in electronic devices based on two-dimensional (2D) materials limited optical absorptivity. This was demonstrated using 2D SnS2, a promising material band gap of about 2.3 eV and poor absorption the range spectrum. Field-effect transistors pristine SnS2 show n-type transport high on–off ratios. Decoration isolated MAPbI3...
The Debye–Waller factor plots for S 2p core-level, based on temperature-dependent X-ray photoemission measurements quasi-one-dimensional (1D) chains of TiS3, suggest effective Debye temperatures the two different types sulfur coordination are 464 ± 35 K and 547 26 K, respectively. in ZrS3 found to be 558 30 667 again, coordination. differences species both TiS3 ZrS3, consistent with existence inequivalent environments. Moreover, considerably higher temperature core-level comparison that...
X-ray photoemission spectroscopy (XPS) has been used to examine the interaction between Au and HfS3 at Au/HfS3 interface. XPS measurements reveal dissociative chemisorption of O2, leading formation an oxide Hf surface HfS3. This hafnium oxide, along with weakly chemisorbed molecular species, such as O2 H2O, are likely responsible for observed p-type characteristics reported elsewhere. devices exhibit n-type behaviour if measured in vacuum but turn air. thickness-dependent provide clear...
We report the modification of a gas phase ultrafast electron diffraction (UED) instrument that enables experiments with both and condensed matter targets, where time-resolved experiment sub-picosecond resolution is demonstrated solid state samples. The relies on hybrid DC-RF acceleration structure to deliver femtosecond pulses target, which synchronized laser pulses. are used excite sample probe structural dynamics, respectively. new system added capabilities perform transmission UED thin It...
Few-layered HfS 3 nanoribbons exhibit n-type conductivity and a large photoresponse to visible light. The photocurrent strongly depends on the polarization direction of excitation laser due highly anisotropic quasi-1D crystal structure .
Monolayers of Ti
MXenes are a large family of two-dimensional transition metal carbides, nitrides, and carbonitrides. While have great potential for applications in analytical chemistry, most the studies this field focused on Ti3C2Tx, popular MXene material. For example, several employed Ti3C2Tx as an adsorbent trace detection toxic analytes, but there is limited knowledge utility other materials application. In work, we investigated Cr2TiC2Tx, one least studied MXenes, application material...
Scalable fabrication of graphene nanoribbons with narrow band gaps has been a nontrivial challenge. Here, we have developed unique approach to access by using hybrid edge structures. Bottom-up liquid-phase synthesis bent N=6/8 armchair (AGNRs) achieved in high efficiency through copolymerization between an ortho-terphenyl monomer and naphthalene-based monomer, followed Scholl oxidation. An unexpected 1,2-aryl migration discovered, which is responsible for introducing kinked structures the...