Related papers: Photoelectron diffraction of twisted bilayer graph…
Bilayer graphene field-effect transistors (BLG-FETs), unlike conventional semiconductors, are greatly sensitive to potential fluctuations due to the charged impurities in high-k gate stacks since the potential difference between two layers…
X-ray photoelectron diffraction is a powerful tool for determining the structure of clean and adsorbate-covered surfaces. Extending the technique into the ultrafast time domain will open the door to studies as diverse as the direct…
The recently developed precession electron diffraction (PED) technique in scanning transmission electron microscopy (STEM) has been used to elucidate the local strain distribution and crystalline misorientation in CMOS fabricated strained…
A unique attribute of atomically thin quantum materials is the in-situ tunability of their electronic band structure by externally controllable parameters like electrostatic doping, electric field, strain, electron interactions, and…
Photoelectron emission microscopy PEEM is a powerful tool to spectroscopically image dynamic surface processes at the nanoscale but is traditionally limited to ultra high or moderate vacuum conditions. Here, we develop a novel grapheme…
Owing to the interaction between the layers, the twisted bilayer two-dimensional materials exhibit numerous unique optical and electronic properties different from the monolayer counterpart, and have attracted tremendous interests in…
We demonstrate that stacking layered materials allows a novel type of strain engineering where each layer is strained independently, which we call heterostrain. We combine detailed structural and spectroscopic measurements with…
The introduction of 'twist' or relative rotation between two atomically thin van der Waals (vdW) membranes gives rise to periodic Moire potential, leading to a substantial altercation of the band structure of the planar assembly. While most…
We theoretically study the dynamic screening properties of bilayer graphene within the random phase approximation assuming quadratic band dispersion and zero gap for the single-particle spectrum. We calculate the frequency dependent…
The electronic structure of few-layer graphene (FLG) samples with crystalline order was investigated experimentally by infrared absorption spectroscopy for photon energies ranging from 0.2 - 1 eV. Distinct optical conductivity spectra were…
We investigate the structural damage of graphene underlying dielectrics (HfO2 and Al2O3) by remote plasma-enhanced atomic layer deposition (PE-ALD). Dielectric film is grown on bilayer graphene without inducing significant damage to the…
In pyrocarbon materials, the width of the Raman D band (FWHMD) is very sensitive to low energy structural defects (e.g., disorientations of the graphene layers). The correlation between the two parameters, FWHMD and OA (as derived from…
We studied the interlayer coupling and decoupling of bilayer graphene (BLG) by using spatially resolved electron energy loss spectroscopy (EELS) with a monochromated electron source. We correlated the twist-angle-dependent energy band…
Artificially constructed van der Waals heterostructures (vdWHs) provide an ideal platform for realizing emerging quantum phenomena in condensed matter physics. Two methods for building vdWHs have been developed: stacking two-dimensional…
We study how the electronic structure of the bilayer graphene (BLG) is changed by electric field and strain from {\it ab initio} density-functional calculations using the LMTO and the LAPW methods. Both hexagonal and Bernal stacked…
The optical and electronic properties of van der Waals (vdW) heterostructures depend strongly on the atomic stacking order of the constituent layers. This is exemplified by periodic variation of the local atomic registry, known as moire…
The salient property of the electronic band structure of twisted bilayer graphene (TBG), at the so-called magic angle (MA), is the emergence of flat bands around the charge neutrality point. These bands are associated with the observed…
The field of two-dimensional (2D) materials has expanded to multilayered systems where electronic, optical, and mechanical properties change-often dramatically-with stacking order, thickness, twist, and interlayer spacing [1-5]. For…
We propose and evaluate the graphene layer (GL) infrared photodetectors (GLIPs) based on the van der Waals (vdW) heterostructures with the radiation absorbing GLs. The operation of the GLIPs is associated with the electron photoexcitation…
One of the primary uses for transmission electron microscopy (TEM) is to measure diffraction pattern images in order to determine a crystal structure and orientation. In nanobeam electron diffraction (NBED) we scan a moderately converged…