Determination of Diffusion Length of Carriers in Graphene Using Contactless Photoelectromagnetic Method of Investigations

2015 ◽  
Vol 1727 ◽  
Author(s):  
Marian Nowak ◽  
Barbara Solecka ◽  
Marcin Jesionek
Keyword(s):  
Magnetic Field ◽  
Spatial Distribution ◽  
Glass Substrate ◽  
Diffusion Length ◽  
Optoelectronic Devices ◽  
Illumination Intensity ◽  
Theoretical Dependence ◽  
Field Induction ◽  
Graphene Films

ABSTRACTThe photoelectromagnetic (PEM) investigations are proposed for determination of diffusion length of carriers in graphene. The presented measurements are performed in Corbino configuration using noncontact technique. The circular PEM currents are detected in an outer coil by induction if illumination intensity is periodically varied. The theoretical dependence of PEM response on magnetic field induction, intensity and spatial distribution of illumination as well as on frequency of illumination chopping is presented. Experimental PEM data are presented for graphene films grown by CVD processing on a cooper foil and transferred onto a glass substrate. The presented method of investigations should be essential for development of graphene electronic and optoelectronic devices.

Damping Properties of Magnetorheological Elastomers

2017 ◽  
Vol 1143 ◽  
pp. 247-252 ◽  
Author(s):  
Petrica Eduard Chirila ◽  
Ionel Chirica ◽  
Elena Felicia Beznea
Keyword(s):  
Magnetic Field ◽  
Smart Materials ◽  
Magnetic Field Induction ◽  
Reactive Force ◽  
Damping Properties ◽  
Magnetorheological Elastomers ◽  
Field Induction ◽  
Field Action ◽  
The Magnetic Field

Magnetorheological elastomers (MREs) are a kind of smart materials, which change the mechanical properties (viscoelastic characteristics) under the magnetic field action. In the paper the determination of damping properties (reactive force) of specimens made out of magnetorheological elastomers is presented. The specimens made out of MREs have been fabricated as a composite with matrix made out of silicone rubber with certain contents of magnetisable particles (carbonyl iron powder). The cylindrical specimens have been tested in compression loading, controlled by an electro-mechanic system. The MRE characteristics of the specimens have been determined in the presence of a magnetic field produced with an electromagnet (coil device). The reactive force occurring in the MRE specimen has been determined on the basis of the measured data during loading. The variation curves of the reactive force versus magnetic field induction are drawn. As a conclusion, the rigidity of the MRE specimen is increasing since the magnitude of the magnetic field induction is increasing.

scholarly journals Quantitative Determination of the Surface Distribution of Supported Metal Nanoparticles: A Laser Ablation–ICP–MS Based Approach

Chemosensors ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 77
Author(s):  
Davide Spanu ◽  
Gilberto Binda ◽  
Marcello Marelli ◽  
Laura Rampazzi ◽  
Sandro Recchia ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Laser Ablation ◽  
Quantitative Determination ◽  
Metal Nanoparticles ◽  
Total Mass ◽  
Functional Materials ◽  
Metal Extraction ◽  
Ms Analysis ◽  
Icp Ms

A laser ablation–inductively coupled plasma–mass spectrometry (LA–ICP–MS) based method is proposed for the quantitative determination of the spatial distribution of metal nanoparticles (NPs) supported on planar substrates. The surface is sampled using tailored ablation patterns and the data are used to define three-dimensional functions describing the spatial distribution of NPs. The volume integrals of such interpolated surfaces are calibrated to obtain the mass distribution of Ag NPs by correlation with the total mass of metal as determined by metal extraction and ICP–MS analysis. Once this mass calibration is carried out on a sacrificial sample, quantifications can be performed over multiple samples by a simple micro-destructive LA–ICP–MS analysis without requiring the extraction/dissolution of metal NPs. The proposed approach is here tested using a model sample consisting of a low-density polyethylene (LDPE) disk decorated with silver NPs, achieving high spatial resolution over cm2-sized samples and very high sensitivity. The developed method is accordingly a useful analytical tool for applications requiring both the total mass and the spatial distribution of metal NPs to be determined without damaging the sample surface (e.g., composite functional materials and NPs, decorated catalysts or electrodic materials).

scholarly journals Determination of the hyperfine magnetic field in magnetic carbon-based materials: DFT calculations and NMR experiments

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Jair C. C. Freitas ◽  
Wanderlã L. Scopel ◽  
Wendel S. Paz ◽  
Leandro V. Bernardes ◽  
Francisco E. Cunha-Filho ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Dft Calculations ◽  
Hyperfine Magnetic Field ◽  
Magnetic Carbon ◽  
Carbon Based

A-Si:H Ambipolar Diffusion Length and Effective Lifetime Measured by Flying Spot Technique (FST)

1991 ◽  
Vol 219 ◽  
Author(s):  
M. Vieira ◽  
R. Martins ◽  
E. Fortunato ◽  
F. Soares ◽  
L. Guimaraes
Keyword(s):  
Laser Beam ◽  
Transient Analysis ◽  
Diffusion Length ◽  
Transport Equations ◽  
Ambipolar Diffusion ◽  
Schottky Barriers ◽  
Effective Lifetime ◽  
Asymmetrical Distribution ◽  
Flying Spot

ABSTRACTThe determination of the ambipolar diffusion length, L*, and the effective lifetime, τ*, in p/i and a-Si:H Schottky barriers (ITO/p/a-Si:H/Al-Si; Cr/a-Si:H/Cr/Ag) have been determined by Flying Spot Technique, FST. This technique consists in the transient analysis of the photocurrent/photopotential induced by a laser beam that moves perpendicularly to the structure with a constant motion ratio, at different velocities. Taking into account the competition between the diffusion/drift velocities of the excess carriers and the velocity of the flying spot, it is possible to solve the transport equations and to compute separately L* and τ*, from the asymmetrical distribution responses.

Sign in / Sign up

Export Citation Format

Share Document