Yu-Meng You

Thickness-Dependent Reversible Hydrogenation of Graphene Layers

In this work, graphene layers on SiO(2)/Si substrate have been chemically decorated by radio frequency hydrogen plasma. Hydrogen coverage investigation by Raman spectroscopy and micro-X-ray photoelectron spectroscopy characterization demonstrates that the hydrogenation of single layer graphene on SiO(2)/Si substrate is much less feasible than that of bilayer and multilayer graphene. Both the hydrogenation and dehydrogenation process of the graphene layers are controlled by the corresponding energy barriers, which show significant dependence on the number of layers. The extent of decorated carbon atoms in graphene layers can be manipulated reversibly up to the saturation coverage, which facilitates engineering of chemically decorated graphene with various functional groups via plasma techniques.

Edge chirality determination of graphene by Raman spectroscopy

Raman imaging of single layer micromechanical cleavage graphene was carried out. The intensity of disorder-induced Raman feature (D band at ∼1350cm−1) was found to be correlated to the edge chirality: it is stronger at the armchair edge and weaker at the zigzag edge. This shows that Raman spectroscopy is a reliable and practical method to identify the chirality of graphene edge and hence the crystal orientation. The determination of graphene chirality is critically important for fundamental study of graphene as well as applications of graphene-based devices.

Reduction of Fermi velocity in folded graphene observed by resonance Raman spectroscopy

The

High-Temperature Ferroelectricity and Photoluminescence in a Hybrid Organic–Inorganic Compound: (3-Pyrrolinium)MnCl3

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High responsivity phototransistors based on few-layer ReS2 for weak signal detection

layer folded graphene sheets that deviate from

Bandgap Engineering of Lead‐Halide Perovskite‐Type Ferroelectrics

AB

Broadband Photovoltaic Detectors Based on an Atomically Thin Heterostructure

stacking are successfully fabricated and their electronic structures are investigated by Raman spectroscopy. Significant blueshift of the 2D band of folded graphene compared to that of single layer graphene (SLG) is observed. This is attributed to SLG-like electronic structure of folded graphene but with slowing down of Fermi velocity (as much as

Direct determination of the crystallographic orientation of graphene edges by atomic resolution imaging

\ensuremath{\sim}5.6%

Molecular Ferroelectric with Most Equivalent Polarization Directions Induced by the Plastic Phase Transition

). Different amount of blueshift of 2D band is observed for different folded graphenes, which may correspond to the different twist angle and/or separation between the two layers, resulting in different Fermi velocity of folded graphenes. Electronic structure of

A Three-Dimensional Molecular Perovskite Ferroelectric: (3-Ammoniopyrrolidinium)RbBr3

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