A5089640698- Graphene research and applications
- Molecular Junctions and Nanostructures
- Ultrasonics and Acoustic Wave Propagation
- Carbon Nanotubes in Composites
- Quantum and electron transport phenomena
- Geophysical Methods and Applications
- Quantum Dots Synthesis And Properties
- Advancements in Semiconductor Devices and Circuit Design
- Fullerene Chemistry and Applications
- Wood Treatment and Properties
- Advanced Sensor and Energy Harvesting Materials
- Thermal properties of materials
- Intermetallics and Advanced Alloy Properties
- Organic Electronics and Photovoltaics
- Combustion and flame dynamics
- Electronic Packaging and Soldering Technologies
- Semiconductor Quantum Structures and Devices
- Machine Learning in Materials Science
- Nanowire Synthesis and Applications
- 2D Materials and Applications
- Flow Measurement and Analysis
- Non-Destructive Testing Techniques
- Surface and Thin Film Phenomena
- Diamond and Carbon-based Materials Research
- Thermal Radiation and Cooling Technologies
Swiss Federal Laboratories for Materials Science and Technology
2015-2025
University of Saskatchewan
1988
Abstract Atomically precise graphene nanoribbons (GNRs) are increasingly attracting interest due to their largely modifiable electronic properties, which can be tailored by controlling width and edge structure during chemical synthesis. In recent years, the exploitation of GNR properties for devices has focused on integration into field‐effect‐transistor (FET) geometries. However, such FET have limited electrostatic tunability presence a single gate. Here, device 9‐atom wide armchair...
Atomically precise graphene nanoribbons (GNRs) are a promising emerging class of designer quantum materials with electronic properties that tunable by chemical design. However, many challenges remain in the device integration these materials, especially regarding contacting strategies. We report on uniaxially aligned and non-aligned 9-atom wide armchair (9-AGNRs) field-effect transistor geometry using electron beam lithography-defined electrodes. This approach yields controlled electrode...
Abstract Hybrid graphene‐colloidal PbS quantum dots (QDs) phototransistors are promising to overcome the geometrical restrictions of photodetectors flat substrates. While compatible with conformal manufacturing, experimental demonstration their application curved surfaces remains elusive. This work demonstrates seamless integration an infrared (IR) photodetector a polymer optical fiber (POF) by wrapping graphene around POF 1 mm in diameter and, subsequently, inkjet printing QDs onto surface....
Abstract Wireless medical sensors typically utilize electromagnetic coupling or ultrasound for energy transfer and sensor interrogation. Energy management is a complex aspect that often limits the applicability of implantable systems. In this work, we report new passive temperature sensing scheme based on an acoustic metamaterial made silicon embedded in polydimethylsiloxane matrix. Compared to other approaches, concept implemented without additional electrical components situ need...
Polymer nanocomposites (PNCs), which feature a hybrid network of soft polymers filled with nanoparticles, hold promise for application in robots due to their tunable physiochemical properties. Under certain environmental conditions, PNCs undergo stimuli-responsive structural rearrangement and transform the energy ambient environment into diverse uses, example, repairing injuries reconfiguring shapes materials. We develop ability thermal-responsive restructuring by stepwise assembly...
Abstract A novel air-coupled ultrasound (ACU) 120 kHz normal transmission system enabled successful imaging of bonding and saw cut defects in multilayered glulam beams up to 280 mm height with a signal-to-noise ratio (SNR) 40 dB. The main wave propagation paths were modeled; quasi-longitudinal quasi-transverse modes coupled each lamella the sound field was found be shifted from insonification axis as function ring angle, leading interference receiver 15 dB amplitude variability defect-free...
Reactive nano-multilayers (RNMLs), which are able to undergo a self-heating exothermal reaction, can, e.g., be utilised as local heat source for soldering or brazing. Upon joining with RNMLs, the produced by reaction must carefully adjusted system in order provide sufficient bond formation while avoiding damaging of components excessive heat. This balance strongly depends on thermal properties components: low conductivity leads concentration within zone adjacent RNML, high fast dissipation...
Abstract Mapping the thermal transport properties of materials at nanoscale is critical importance for optimizing heat conduction in devices. Several methods to determine conductivity have been developed, most them yielding an average value across sample, thereby disregarding role local variations. Here, we present a method spatially resolved assessment suspended graphene by using combination confocal Raman thermometry and finite-element calculations-based fitting procedure. We demonstrate...
Air-coupled ultrasound (ACU) is increasingly used for nondestructive testing (NDT). With ACU, no contact or coupling agent (e.g., water and gel) needed between transducers test sample, which provides high measurement reproducibility. However, in production, a minimum separation often necessary the sample to avoid contamination transducer damage. Due wave diffraction, collimation of beam decreases larger propagation distances, ACU images become blurred show lower defect lateral resolution...
Medical ultrasonic arrays are typically characterized in controlled water baths using measurements by a hydrophone, which can be translated with positioning stage. Characterization of 3D acoustic fields conventionally requires at each spatial location, is tedious and time-consuming, may prohibitive given limitations experimental setup (e.g., the bath stage) measurement equipment (i.e., hydrophone). Moreover, development new ultrasound sequences modalities, multiple often required to...
Bottom-up synthesized graphene nanoribbons (GNRs) are increasingly attracting interest due to their atomically controlled structure and customizable physical properties. In recent years, a range of GNR-based field-effect transistors (FETs) has been fabricated, with several demonstrating quantum-dot (QD) behavior at cryogenic temperatures. However, understanding the relationship between charge-transport characteristics number GNRs in device is challenging, as length location junction not...
Quantitative and reproducible air-coupled ultrasound (ACU) testing requires characterization of the volumetric pressure fields radiated by ACU probes. In this paper, a closed-form reradiation method combining Rayleigh-Sommerfeld integral time-reversal acoustics is proposed, which allows calculation both near- field far-field based on single-plane measurement. The was validated for 3-D (circular, square) 2-D (rectangular) planar transducers in 50-230 kHz range. were scanned with calibrated...
The energetics of graphene/pentacene nanostructures is determined by conductive-AFM measurements combined with analytical models and related to the organization pentacene molecules at interface as deduced from micro-Raman spectroscopy.
Among the family of 2D materials, graphene is ideal candidate as top or interlayer electrode for hybrid van der Waals heterostructures made organic thin films and materials due to its high conductivity mobility inherent ability forming neat interfaces without diffusing in adjacent layer. Understanding charge injection mechanism at graphene/organic semiconductor therefore crucial develop electronic devices. In particular, Gr/C60 are promising building blocks future n-type vertical transistors...
Colloidal quantum dots (cQDs), semiconductor materials with widely tunable properties, can be printed in submicrometer patterns through electrohydrodynamic printing, avoiding aggressive photolithography steps. Postprinting ligand exchange determines the final optoelectronic properties of cQD structures. However, achieving a complete bulk is challenging, and conventional vibrational analysis lacks required spatial resolution. Infrared nanospectroscopy enables quantitative signals structural...
The joining of macroscopic films vertically aligned multiwalled carbon nanotubes (CNTs) to titanium substrates is demonstrated by active vacuum brazing at 820 °C with a Ag-Cu-Ti alloy and 880 Cu-Sn-Ti-Zr alloy. methodology was elaborated in order enable the production highly electrically thermally conductive CNT/metal substrate contacts. interfacial electrical resistances joints were measured be as low 0.35
Hybrid van der Waals heterostructures based on 2D materials and/or organic thin films are being evaluated as potential functional devices for a variety of applications. In this context, the graphene/organic semiconductor (Gr/OSC) heterostructure could represent core element to build future vertical transistors two back-to-back Gr/OSC diodes sharing common graphene sheet, which functions base electrode. However, assessment still requires deeper understanding charge carrier transport across...
Abstract Graphene nanogaps are considered as essential building blocks of two-dimensional electronic circuits, they offer the possibility to interconnect a broad range atomic-scale objects. Here we provide an insight into microscopic processes taking place during formation graphene through detailed analysis their low-frequency noise properties. Following evolution level, identify fundamentally different regimes throughout nanogap formation. By modeling resistance and bias dependence noise,...