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Single crystal diamond has been used as a substrate to support single layer graphene grown by chemical vapor deposition methods. It is possible to chemically functionalise the diamond surface, and in the present case H-, F-, O-, and N-group have been purposefully added prior to graphene deposition. The electronic properties of the resultant heterostructures vary strongly; a p-type layer with good mobility and a band gap of ∼0.7 eV is created when H-terminated diamond layers are used, whilst a layer with more metallic-like character (high carrier density and low carrier mobility) arises when N(O)-terminations are introduced. Since it is relatively easy to pattern these functional groups on the diamond surface, this suggests that this approach may offer an exciting route to 2D device structures on single layer graphene sheets. [ABSTRACT FROM AUTHOR]

Significant variation in the charge transport behaviour in graphene oxide (GO) ranging from Schottky to Poole-Frenkel and to space charge limited transport exists. These have been extensively reported in the literature. However, the validity of such conventional charge transport models meant for delocalized carriers, to study charge transport through localised states in GO, a disordered semiconductor is open to question. In this work, we use the concept of transport energy (TE) to model charge transport in lightly reduced GO (RGO) and demonstrate that the TE calculations match well with temperature dependent experimental I-V data on RGO. We report on a temperature dependent TE ranging from a few 10 meV to 0.1 eV in slightly reduced GO. Last, we point out that, despite the success of several delocalised charge transport models in estimating barrier heights that resemble the TE level, they remain largely accidental and lack the insight in which the TE concept provides in understanding charge transport in RGO. [ABSTRACT FROM AUTHOR]

Realization of the direct charge transfer at metal–semiconductor interfaces is a long-standing goal of both fundamental and technological significance. Here we report the synthesis of a colloidal Sb2Se3–Au core–shell nanorod as a model system to demonstrate an efficient direct charge transfer from an Au shell to Sb2Se3 core when the metal is selectively excited at the plasmonic wavelength. In our experiments, direct charge transfer by the Landau damping of the plasmons of metal shell significantly enhances the excited state population that results in an unprecedented ultrafast third-order nonlinear optical response as a function of the plasmon-excitation detuning wavelength. The single step photo-induced charge transfer analogous to the intramolecular electronic transition in molecules is probed by ultrafast transient absorption, which reveals that the electrons are directly transferred from the Fermi level of Au to the unoccupied levels of Sb2Se3 in less than 150 fs. First principles density functional theory calculations indicate that the hybridized eigenstates of the strongly coupled system are delocalized across the metal–semiconductor interfaces. By formulating the theoretical models, we connect our experimental results to the theory. [ABSTRACT FROM AUTHOR]

Layered transition metal dichalcogenides (TMDs) provide an ideal platform for exploring the effects of dimensionality on correlated electronic phases such as charge density wave (CDW) order. When TMDs are reduced in thickness to the 2-D limit, it is expected that the substrates will exert a considerable influence on the electron states. Here, we report a study of the charge density wave state in 1T-TiSe2 nanosheets of different thicknesses when the sheets are encapsulated by hexagonal Boron Nitride or supported on the SiO2 substrate. Our results show that dimensionality reduction results in an enhancement of CDW order and that disorder and substrate phonons tend to destroy CDW order, preventing observation of intrinsic CDW transition in ultrathin samples. Encapsulated 10 nm thick 1T-TiSe2 samples exhibit intrinsic CDW with transition temperature as high as 235 K. Our study points out that choosing the right substrate is important in the search for room temperature CDW materials. [ABSTRACT FROM AUTHOR]

Magnetic characterization of ZnO nanowires (NW) decorated with thiol-capped Ag nanoclusters (NCs) reveals spontaneous field-dependent magnetization and hysteresis at room temperature. The saturation magnetization is temperature independent for the 13 nm thiol-capped Ag NCs but unexpectedly increases with temperature for the 4 nm thiol-capped Ag NCs. The high magnetic moment results from the efficient dispersal of Ag NCs on the ZnO NW scaffold and charge transfer interaction between Ag and ZnO. The anomalous magnetic behavior in 4 nm NCs may be due to the spin reorientation of Ag–S dipoles mediated by Zn–S dipoles. [ABSTRACT FROM AUTHOR]

Uniformly distributed ZnO nanorods with diameter 80–120 nm and 2 μm long have been grown at low temperatures on gallium nitride (GaN) by using the inexpensive aqueous solution method. The formation of the ZnO nanorods and the growth parameters are controlled by reactant concentration, temperature and pH. No catalyst is required. The x-ray diffraction (XRD) and transmission electron microscopy (TEM) studies show that the ZnO nanorods are single crystals and they grow along the c axis of the crystal plane. The room temperature photoluminescence (PL) measurements have shown ultraviolet peaks at 388 nm with high intensity, which are comparable to those found in high quality ZnO films. The mechanism of the nanorod growth in the aqueous solution is also proposed. [ABSTRACT FROM AUTHOR]

Examines the dependence of adhesion on topography and material inhomogeneities in doped and undoped polycarbonates. Use of atomic force microscopy; Correlation between adhesion magnitude and surface curvature; Spatial adhesion maps of doped polymers.