Yande Que

The Chinese University of Hong Kong | CUHK · Department of Physics

Single-crystalline transition metal films are ideal playing fields for the epitaxial growth of graphene and graphene-base materials. Graphene-silicon layered structures were successfully constructed on Ir(111) thin film on Si substrate with an yttria-stabilized zirconia buffer layer via intercalation approach. Such hetero-layered structures are com...

Structural engineering opens a door to manipulating the structures and thus tuning the properties of two-dimensional materials. Here, we report a reversible structural transition in honeycomb CuSe monolayer on Cu(111) through scanning tunneling microscopy (STM) and Auger electron spectroscopy (AES). Direct selenization of Cu(111) gives rise to the...

The interplay of topology and superconductivity has become a subject of intense research in condensed matter physics for the pursuit of topologically non-trivial forms of superconducting pairing. An intrinsically normal-conducting material can inherit superconductivity via electrical contact to a parent superconductor via the proximity effect, usua...

Structural engineering opens a door to manipulating the structures and thus tuning the properties of two-dimensional materials. Here, we report a reversible structural transition in honeycomb CuSe monolayer on Cu(111) through scanning tunneling microscopy (STM) and Auger electron spectroscopy (AES). Direct selenization of Cu(111) gives rise to the...

Here, we demonstrate two reliable routes for the fabrication of armchair-edge graphene nanoribbons (GNRs) on TbAu2/Au(111), belonging to a class of two-dimensional ferromagnetic rare earth-gold intermetallic compounds. On-surface synthesis directly on TbAu2 leads to the formation of GNRs, which are short and interconnected with each other. In contr...

Controlling the atomic configurations of structural defects in graphene nanostructures is crucial for achieving desired functionalities. Here, we report the controlled fabrication of high-quality single-crystal and bicrystal graphene nanoislands (GNI) through a unique top-down etching and post-annealing procedure on a graphite surface. Low-temperat...

Surface alloying is a straightforward route to control and modify the structure and electronic properties of surfaces. Here, We present a systematical study on the structural and electronic properties of three novel rare earth-based intermetallic compounds, namely ReAu2 (Re = Tb, Ho, and Er), on Au(111) via directly depositing rare-earth metals ont...

The construction of atomically-precise carbon nanostructures holds promise for developing novel materials for scientific study and nanotechnology applications. Here we show that graphene origami is an efficient way to convert graphene into atomically-precise, complex, and novel nanostructures. By scanning-tunneling-microscope manipulation at low te...

Adsorption of chalcogen atoms on metal surfaces have attracted increasing interest both for the fundamental research and industrial applications. Here, we report a systematic study of selenium (Se) adsorption on Au(111) at varies substrate temperatures by scanning tunneling microscopy. At room temperature, small Se clusters are randomly dispersed o...

Rear-earth on metal may form two-dimensional (2D) intermetallic compound whose properties can be further modulated by the underlying substrate periodicity and coupling. Here, we present a combinational and systematic investigation with scanning tunneling microscopy/spectroscopy (STM/STS) and density functional theory (DFT) calculations on erbium (E...

The highest frequency of the electric signal that a conventional scanning tunneling microscope (STM) can process typically lies in the kilohertz regime, imposing a limitation on its temporal resolution to the submillisecond regime. When extracting (feeding) the high frequency, or radio-frequency (RF), signal out of (into) the tunnel junction, the m...

Precisely folding nanographene Graphene nanostructures that would result from folding or rolling graphene monolayers or bilayers have been predicted to have a number of interesting electronic properties, but control over such folding processes has been limited. Chen et al. used a scanning tunneling microscope tip to fold and unfold graphene nanoisl...

We investigate the morphology evolution and electronic properties of MgO islands grown on Ag(001) substrate by reactive deposition method using low temperature scanning tunneling microscopy/spectroscopy (LT-STM/STS) and low-energy electron diffraction (LEED). By pushing the Mg/O2 ratio to the Mg-rich limit, we observe an edge transformation from th...

The cover image is based on the Research Article Role of surface microstructure of Mo back contact on alkali atom diffusion and Ga grading in Cu(In,Ga)Se2 thin film solar cells by Junbo Gong et al., DOI: 10.1002/ese3.304.

Iridium is a promising substrate for self-limiting growth of graphene. However, single-crystalline graphene can only be fabricated over 1120 K. The weak interaction between graphene and Ir makes it challenging to grow graphene with a single orientation at a relatively low temperature. Here, we report the growth of large-scale, single-crystalline gr...

While the major function of molybdenum (Mo) back contact on soda‐lime glass (SLG) substrate in Cu(In,Ga)Se2 (CIGS) solar cells is to provide good adhesion and good conductivity, its role as the transportation channel for alkali elements from SLG substrate to CIGS layer has often been overlooked. In this work, we have intentionally fabricated tri‐la...

We investigate the interactions between two symmetric monovacancy defects in graphene grown on Ru (0001) after silicon intercalation by combining first-principles calculations with scanning tunneling microscopy (STM). First-principles calculations based on free-standing graphene show that the interaction is weak and no scattering pattern is observe...

Finite-sized graphene sheets, such as graphene nanoislands (GNIs), are pro-mising candidates for practical applications in graphene-based nanoelectronics. GNIs with well-defined zigzag edges are predicted to have spin-polarized edge-states similar to those of zigzag-edged graphene nanoribbons, which can achieve graphene spintronics. However, it has...

The growth of polycyclic aromatic hydrocarbon (PAH) molecular coronene film on various substrates and the subsequent doping of potassium under ultrahigh vacuum (UHV) conditions have been systematically investigated by low-temperature scanning tunneling microscopy and spectroscopy (STM/STS). The crystalline structures and molecular orientations of c...

Unlike graphene sheets, graphene nanoribbons (GNRs) can exhibit semiconducting band gap characteristics that can be tuned by controlling impurity doping and the GNR widths and edge structures. However, achieving such control is a major challenge in the fabrication of GNRs. Chevron-type GNRs were recently synthesized via surface-assisted polymerizat...

Silicon-based two-dimensional (2D) materials are uniquely suited for integration in Si-based electronics. Silicene, an analog of graphene, was recently fabricated on several substrates and was used to make a field-effect transistor. Here, we report that, when Ru(0001) is used as a substrate, a range of distinct monolayer silicon structures forms, e...

High-quality single-layered and bilayered graphene (SLG and BLG) was synthesized on copper foil surfaces by controllable chemical vapor deposition (CVD). Impurity nanoparticles formed on the copper foil surface by hightemperature annealing were found to play a crucial role in the growth of BLG. Analysis of energy-dispersive spectrometry (EDS) data...

Silica (SiO2) islands with a dendritic structure were prepared on polycrystalline copper foil, using silane (SiH4) as a precursor, by annealing at high temperature. Assisted by copper vapor from bare sections of the foil, single-layer hexagonal graphene domains were grown directly on the SiO2 islands by chemical vapor deposition. Scanning electron...

The growth, atomic structure, and electronic property of trilayergraphene (TLG) on Ru(0001) were studied by low temperature scanning tunneling microscopy and spectroscopy in combined with tight-binding approximation (TBA) calculations. TLG on Ru(0001) shows a flat surface with a hexagonal lattice due to the screening effect of the bottom two layers...

An efficient method based on atomic force microscopy (AFM) has been developed to characterize silicon intercalated graphene grown on single crystalline Ir(111) thin films. By combining analyses of the phase image, force curves, and friction–force mapping, acquired by AFM, the locations and coverages of graphene and silicon oxide can be well disting...

The Pb intercalation at the interface of monolayer graphene (MG) and Ru(0001) is studied by means of low temperature scanning tunneling microscopy (LT-STM) and Raman spectroscopy. Despite of being covered by MG, the atomic structures of the Pb layer formed between MG and Ru(0001) have been directly imaged using LT-STM. The Pb layer intercalated und...

High quality sub-monolayer, monolayer, and bilayer graphene were grown on Ru(0001). For the sub-monolayer graphene, the size of graphene islands with zigzag edges can be controlled by the dose of ethylene exposure. By increasing the dose of ethylene to 100 Langmuir at a high substrate temperature (800 °C), high quality single-crystalline monolayer...

Four kinds of defects are observed in graphene grown on Ru (0001) surfaces. After cobalt deposition at room temperature, the cobalt nanoclusters are preferentially located at the defect position. By annealing at 530°C, cobalt atoms intercalate at the interface of Graphene/Ru (0001) through the defects. Further deposition and annealing increase the...

We review the way to fabricate large-scale, high-quality and single crystalline graphene epitaxially grown on Ru(0001) substrate. A moiré pattern of the graphene/Ru(0001) is formed due to the lattice mismatch between graphene and Ru(0001). This superstructure gives rise to surface charge redistribution and could behave as an ordered quantum dot arr...

Large-area bilayer graphene (BG) is grown epitaxially on Ru(0001) surface and characterized by low temperature scanning tunneling microscopy. The lattice of the bottom layer of BG is stretched by 1.2%, while strain is absent from the top layer. The lattice mismatch between the two layers leads to the formation of a moiré pattern with a periodicity...

Intercalations of metals and silicon between epitaxial graphene and its substrates are reviewed. For metal intercalation, seven different metals have been successfully intercalated at the interface of graphene/Ru(0001) and form different intercalated structures. Meanwhile, graphene maintains its original high quality after the intercalation and sho...

We report on temperature-programmed growth of graphene islands on Ru (0001) at annealing temperatures of 700 °C, 800 °C, and 900 °C. The sizes of the islands each show a nonlinear increase with the annealing temperature. In 700 °C and 800 °C annealings, the islands have nearly the same sizes and their ascending edges are embedded in the upper steps...

We report on intercalation of seven kinds of metals--Pt, Pd, Ni, Co, Au, In, and Ce--at the interface between an epitaxially grown graphene layer and a Ru(0001) substrate. Atomic resolution scanning tunneling microscopy images of perfect graphene lattice are obtained on top of these intercalated metals, showing that the high quality of the original...