Showing papers by "Xiaoding Wei published in 2023"

Fast synthesis of large-area bilayer graphene film on Cu

Abstract: Abstract Bilayer graphene (BLG) is intriguing for its unique properties and potential applications in electronics, photonics, and mechanics. However, the chemical vapor deposition synthesis of large-area high-quality bilayer graphene on Cu is suffering from a low growth rate and limited bilayer coverage. Herein, we demonstrate the fast synthesis of meter-sized bilayer graphene film on commercial polycrystalline Cu foils by introducing trace CO 2 during high-temperature growth. Continuous bilayer graphene with a high ratio of AB-stacking structure can be obtained within 20 min, which exhibits enhanced mechanical strength, uniform transmittance, and low sheet resistance in large area. Moreover, 96 and 100% AB-stacking structures were achieved in bilayer graphene grown on single-crystal Cu(111) foil and ultraflat single-crystal Cu(111)/sapphire substrates, respectively. The AB-stacking bilayer graphene exhibits tunable bandgap and performs well in photodetection. This work provides important insights into the growth mechanism and the mass production of large-area high-quality BLG on Cu.

Probing Anisotropic Deformation and Near-Infrared Emission Tuning in Thin-Layered InSe Crystal under High Pressure.

Abstract: Indium selenide (InSe) exhibits high lattice compressibility and an extraordinary capability of tailoring the optical band gap under pressure beyond other 2D materials. Herein, by applying hydrostatic pressure via a diamond anvil cell, we revealed an anisotropic deformation dynamic and efficient manipulation of near-infrared light emission in thin-layered InSe strongly correlated to layer numbers (N = 5-30). As N > 20, the InSe lattice is compressed in all directions, and the intralayer compression leads to widening of the band gap, resulting in an emission blue shift (∼120 meV at 1.5 GPa). In contrast, as N ≤ 15, an efficient emission red shift is observed from band gap shrinkage (rate of 100 meV GPa-1), which is attributed to the predominant uniaxial interlayer compression because of the high strain resistance along the InSe-diamond interface. These findings advance the understanding of pressure-induced lattice deformation and optical transition evolution in InSe and could be applied to other 2D materials.