Tuneable photoconductivity and mobility enhancement in printed MoS 2 /graphene composites

This is the author accepted manuscript. The final version is available from IOP Publishing via the DOI in this record.With the aim of increasing carrier mobility in nanosheet-network devices, we have investigated MoS2–graphene composites as active regions in printed photodetectors. Combining liquid exfoliation and inkjet-printing, we fabricated all-printed photodetectors with graphene electrodes and MoS2–graphene composite channels with various graphene mass fractions (0  ≤  M f  ≤  16 wt%). The increase in channel dark conductivity with M f was consistent with percolation theory for composites below the percolation threshold. While the photoconductivity increased with graphene content, it did so more slowly than the dark conductivity, such that the fractional photoconductivity decayed rapidly with increasing M f. We propose that both mobility and dark carrier density increase with graphene content according to percolation-like scaling laws, while photo-induced carrier density is essentially independent of graphene loading. This leads to percolation-like scaling laws for both photoconductivity and fractional photoconductivity—in excellent agreement with the data. These results imply that channel mobility and carrier density increase up to 100-fold with the addition of 16 wt% graphene.We acknowledge the Science Foundation Ireland (SFI/12/RC/2278), the European Commission (n° 696656, Graphene Flagship) and the European Research Council (FUTURE-PRINT)

Predicting Wave Run-Up using Full ALE Finite Element Approach considering Moving Boundary

A numerical scheme is developed to predict the wave run-up of an unsteady, incompressible viscous flow with free surface by the author$^1$. The method involves a two dimensional finite element with moving boundaries. The governing equations were the Navier-Stokes equations for conservation of momentum and mass for Newtonian fluids, continuity equation, and full nonlinear kinematic free-surface equation. A mapping algorithm was developed to solve highly deformed free surface problems, common in wave propagation. This algorithm transforms the run up model from the physical domain to a computational domain. A new Arbitrary Lagrangian-Eulerian (ALE) finite element modeling technique was used to model the fluid flow and predict the wave modification. Oscillation of the surface profile near the vertical wall was corrected by using a numerical procedure in the mapping function, and also by employing moving boundary technique at the wall point where run up happens. These oscillations are associated with mapping process at the boundaries when a full ALE finite element approach is used in both coordinate directions

Magnetic fabrics and microstructures of the Jurassic Shah-Kuh granite pluton (Lut Block, Eastern Iran) and geodynamic inference

International audienceThe Jurassic Shah-Kuh granite pluton was emplaced in the northeastern part of the Lut Block (Eastern Iran) while this block was a part of the active margin under which the Tethys ocean, that separated Arabia from Central Iran, was subducting. Since this time, the Lut Block has rotated and migrated northward up to its present position. This structural study of the Shah-Kuh aims at strengthening the evidence of its original geodynamical location. Thanks to a systematic collection of oriented samples in the field, well-defined fabric and microstructural patterns were deduced from magnetic fabric measurements and optical microscopy observations. The overall magnetic fabric of the pluton yields vertical, north south striking foliations and shallow lineations plunging to the north. The corresponding microstructures attest to their formation in the magmatic stage, i.e. during emplacement. Subsequent deformation, characterized by (sub)mylonitic microstructures, has modified the original fabric into a northwest and locally a west northwest trend inside a two kilometre-wide corridor. This corridor reflects the trace of a sinistral shear zone that offsets the previous north south magmatic pattern of the pluton. The latter magmatic pattern is proposed to result from the shear component of strain that was parallel to the ancient active margin during pluton emplacement, as a result of strain partitioning, a situation frequently documented at convergent margins. Sinistral shear along an ? E W directed south-facing active margin, assuming a northeastward slip vector for the Tethys ocean during the Jurassic, and accepting a ? 150° counterclockwise rotation of the Lut Block after emplacement of the Shah-Kuh pluton, best explains both the magmatic and the solid-state lineation patterns