Interface construction for charge transportation of ZnO/graphene multilayer films

In order to clarify the effect of interface construction on the charge transportation, the interfaces between zinc oxide (ZnO) and graphene layers were designed into the following types: the smooth interface by direct deposition ZnO layer onto the surface of fresh graphene/glass substrate; the nanoscale rough interface by Ar[Formula: see text] bombardment etching the surface of graphene/glass substrate before deposition of a ZnO layer, and rough ZnO/Ag/graphene interface by deposition Ag first and then ZnO layers on the rough graphene/glass substrate. The results showed that, compared to the morphology of the ZnO/graphene film with smooth surface, the particle sizes of the film with rough interface became fine and their shapes changed from sharp to round. The carriers’ mobility increased from 0.3 cm2 ⋅ V[Formula: see text] ⋅ s[Formula: see text] to 0.6 cm2 ⋅ V[Formula: see text] ⋅ s[Formula: see text] due to the enhancement of the nanocontact at the rough interface between ZnO and graphene layers. In order to improve the electrical properties of ZnO/graphene multilayer film, a 10 nm Ag layer was inserted into the rough graphene/glass and ZnO layer to construct the rough metal interface. The carrier concentration was enhanced from 10[Formula: see text] cm[Formula: see text] of ZnO/graphene to 10[Formula: see text] cm[Formula: see text] ZnO/Ag/graphene films, although the carrier mobility reduced slightly from ZnO/graphene 0.6 to ZnO/Ag/graphene 0.2 cm2 ⋅ V[Formula: see text] ⋅ s[Formula: see text]. The sheet resistance and resistivity of the ZnO/Ag/graphene multilayer film decreased dramatically by inserting the conductive Ag layer, which took the roles of both the provider of charge carriers from Ag layer and bridges of the carriers from graphene layer.

Van der Waals epitaxy of nearly single-crystalline nitride films on amorphous graphene-glass wafer

Van der Waals epitaxy provides a fertile playground for the monolithic integration of various materials for advanced electronics and optoelectronics. Here, a previously unidentified nanorod-assisted van der Waals epitaxy is developed and nearly single-crystalline GaN films are first grown on amorphous silica glass substrates using a graphene interfacial layer. The epitaxial GaN-based light-emitting diode structures, with a record internal quantum efficiency, can be readily lifted off, becoming large-size flexible devices. Without the effects of the potential field from a single-crystalline substrate, we expect this approach to be equally applicable for high-quality growth of nitrides on arbitrary substrates. Our work provides a revolutionary technology for the growth of high-quality semiconductors, thus enabling the hetero-integration of highly mismatched material systems.

Predicting of Impact Strength and Elastic Modulus of Polypropylene/EPDM/Graphene/Glass Fiber Nanocomposites by Response Surface Methodology

In the present manuscript, Response Surface Method (RSM) of the experimental planning was applied to optimize the mechanical properties such as impact strength and elastic modulus of polypropylene (PP)/ethylene propylene dine monomer (EPDM) /grapheme Nano sheets (GnPs)/ glass fiber hybrid nanocomposites. According to a Box-Behnken method, three levels of parameters were used for EPDM (5, 10 and 15 wt.%), GnPs (0, 1 and 2 wt.%) and glass fiber (10, 20 and 30 wt.%). In addition, specimens were studied using differential scanning calorimeter (DSC) and scanning electron microscopy (SEM) to see their morphology and thermal properties. It was discovered that GnPs, glass fiber and EPDM played an important role in impact strength and elastic modulus of the nanocomposites. To reach the maximum value of the impact strength and elastic modulus simultaneously, the best amount of additives was about 0.82 wt.% of GnPs, 30 wt.% of glass fiber and 15 wt.% of EPDM. The gained R2 values and the corresponding diagrams showed a desirable accordance (above 0.93 for all the responses) with the experiments and those guessed by the RSM.

ZnO Nanorod/Graphene Hybrid-Structures Formed on Cu Sheet by Self-Catalyzed Vapor-Phase Transport Synthesis

High crystalline ZnO nanorods (NRs) on Zn pre-deposited graphene/Cu sheet without graphene transfer process have been fabricated by self-catalyzed vapor-phase transport synthesis. Here, the pre-deposited Zn metal on graphene not only serves as a seed to grow the ZnO NRs, but also passivates the graphene underneath. The temperature-dependent photoluminescence spectra of the fabricated ZnO NRs reveal a dominant peak of 3.88 eV at 10 K associated with the neutral-donor bound exciton, while the redshifted peak by bandgap shrinkage with temperature and electron-lattice interactions leads a strong emission at 382 nm at room temperature. The optical absorption of the ZnO NRs/graphene hetero-nanostructure at this ultraviolet (UV) emission is then theoretically analyzed to quantify the absorption amount depending on the ZnO NR distribution. By simply covering the ZnO NR/graphene/Cu structure with the graphene/glass as a top electrode, it is observed that the current-voltage characteristic of the ZnO NR/graphene hetero-nanojunction device exhibits a photocurrent of 1.03 mA at 3 V under a light illumination of 100 μW/cm2. In particular, the suggested graphene/ZnO NRs/graphene hybrid-nanostructure-based devices reveal comparable photocurrents at a bidirectional bias, which can be a promising platform to integrate 1D and 2D nanomaterials without complex patterning process for UV device applications.

Non-enzymatic sensor for determination of glucose based on PtNi nanoparticles decorated graphene

Diabetes has become a universal epidemic in recent years. Herein, the monitoring of glucose in blood is of importance in clinical applications. In this work, PtNi alloy nanoparticles homogeneously dispersed on graphene (PtNi alloy-graphene) was synthesized as a highly effective electrode material for glucose detection. Based on the modified PtNi alloy-graphene/glass carbon (PtNi alloy-graphene/GC) electrode, it is found that the PtNi alloy-graphene/GC electrode exhibited excellent electrocatalytic performance on glucose oxidation. Furthermore, the results from amperometric current–time curve show a good linear range of 0.5–15 mM with the limit of detection of 16 uM (S/N = 3) and a high sensitivity of 24.03 uAmM−1 cm−2. On account of the good selectivity and durability, the modified electrode was successfully applied on glucose detection in blood serum samples.

Robust formation of amorphous Sb2S3 on functionalized graphene for high-performance optoelectronic devices in the cyan-gap

Despite significant progress in the fabrication and application of semiconductor materials for optical emitters and sensors, few materials can cover the cyan-gap between 450 and 500 nm. We here introduce a robust and facile method to deposit amorphous Sb2S3 films with a bandgap of 2.8 eV. By exploiting the tunable functionality of graphene, a two-dimensional material, efficient deposition from a chemical was achieved. Ozone-generated defects in the graphene were shown to be required to enhance the morphology and quality of the material and comprehensive characterization of the seed layer and the Sb2S3 film were applied to design an optimal deposition process. The resulting material exhibits efficient carrier transport and high photodetector performance as evidenced by unprecedented responsivity and detectivity in semiconductor/graphene/glass vertical heterostructures. (112 A/W, 2.01 × 1012 Jones, respectively).