scholarly journals Ideal optical contrast for 2D material observation using bi-layer antireflection absorbing substrates

Nanoscale ◽  
2019 ◽  
Vol 11 (13) ◽  
pp. 6129-6135 ◽  
Author(s):  
Kevin Jaouen ◽  
Renaud Cornut ◽  
Dominique Ausserré ◽  
Stéphane Campidelli ◽  
Vincent Derycke
Keyword(s):  
Double Layer ◽  
Film Growth ◽  
2D Materials ◽  
High Sensitivity ◽  
Optical Contrast ◽  
2D Material ◽  
Molecular Film

Optimized double-layer antireflection substrates allow observation of 2D materials with greatly enhanced contrast and molecular film growth with ultra-high sensitivity.

scholarly journals The epitaxy of 2D materials growth

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Jichen Dong ◽  
Leining Zhang ◽  
Xinyue Dai ◽  
Feng Ding
Keyword(s):  
Epitaxial Growth ◽  
Density Functional ◽  
Large Scale ◽  
Film Growth ◽  
2D Materials ◽  
Critical Role ◽  
High Symmetry ◽  
Perfect Agreement ◽  
Symmetry Direction ◽  
2D Material

AbstractTwo dimensional (2D) materials consist of one to a few atomic layers, where the intra-layer atoms are chemically bonded and the atomic layers are weakly bonded. The high bonding anisotropicity in 2D materials make their growth on a substrate substantially different from the conventional thin film growth. Here, we proposed a general theoretical framework for the epitaxial growth of a 2D material on an arbitrary substrate. Our extensive density functional theory (DFT) calculations show that the propagating edge of a 2D material tends to align along a high symmetry direction of the substrate and, as a conclusion, the interplay between the symmetries of the 2D material and the substrate plays a critical role in the epitaxial growth of the 2D material. Based on our results, we have outlined that orientational uniformity of 2D material islands on a substrate can be realized only if the symmetry group of the substrate is a subgroup of that of the 2D material. Our predictions are in perfect agreement with most experimental observations on 2D materials’ growth on various substrates known up to now. We believe that this general guideline will lead to the large-scale synthesis of wafer-scale single crystals of various 2D materials in the near future.

Schottky diodes based on 2D materials for environmental gas monitoring: a review on emerging trends, recent developments and future perspectives

2021 ◽  
Author(s):  
Minu Mathew ◽  
Chandra Sekhar Rout
Keyword(s):  
Gas Sensing ◽  
2D Materials ◽  
Schottky Diodes ◽  
High Sensitivity ◽  
Future Perspectives ◽  
Working Temperature ◽  
Emerging Trends ◽  
Gas Sensing Properties ◽  
Recent Developments ◽  
Sensitivity And Selectivity

This review details the fundamentals, working principles and recent developments of Schottky junctions based on 2D materials to emphasize their improved gas sensing properties including low working temperature, high sensitivity, and selectivity.

scholarly journals Topological vectors as a fingerprinting system for 2D-material flake distributions

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Joyce C. C. Santos ◽  
Mariana C. Prado ◽  
Helane L. O. Morais ◽  
Samuel M. Sousa ◽  
Elisangela Silva-Pinto ◽  
...  
Keyword(s):  
Distribution Function ◽  
2D Materials ◽  
Shape Parameters ◽  
Representation System ◽  
Statistical Characterization ◽  
2D Material ◽  
Fast Pace ◽  
Parameter Distributions

AbstractThe production of 2D material flakes in large quantities is a rapidly evolving field and a cornerstone for their industrial applicability. Although flake production has advanced in a fast pace, its statistical characterization is somewhat slower, with few examples in the literature which may lack either modelling uniformity and/or physical equivalence to actual flake dimensions. The present work brings a methodology for 2D material flake characterization with a threefold target: (i) propose a set of morphological shape parameters that correctly map to actual and relevant flake dimensions; (ii) find a single distribution function that efficiently describes all these parameter distributions; and (iii) suggest a representation system—topological vectors—that uniquely characterizes the statistical flake morphology within a given distribution. The applicability of such methodology is illustrated via the analysis of tens of thousands flakes of graphene/graphite and talc, which were submitted to different production protocols. The richness of information unveiled by this universal methodology may help the development of necessary standardization procedures for the imminent 2D-materials industry.

Nanopillar modified high-sensitivity asymmetric Graphene-GaN photodetector

Nanoscale ◽  
2021 ◽  
Author(s):  
Chang Liu ◽  
Xiaodong Li ◽  
Tiangui Hu ◽  
Wenkai Zhu ◽  
Faguang Yan ◽  
...  
Keyword(s):  
Electrical Properties ◽  
High Performance ◽  
2D Materials ◽  
Three Dimensional ◽  
High Sensitivity ◽  
Optical And Electrical Properties ◽  
Two Dimensional

Integration of two dimensional (2D) materials with three dimensional (3D) semiconductors reveals intriguing optical and electrical properties that surpass those of the original materials. Here we report the high performance...

Molecular dynamics method in studies of molecular film growth processes

2006 ◽  
Vol 47 (3) ◽  
pp. 532-548 ◽  
Author(s):  
I. F. Golovnev ◽  
T. V. Basova ◽  
E. K. Koltsov ◽  
I. K. Igumenov
Keyword(s):  
Molecular Dynamics ◽  
Film Growth ◽  
Molecular Dynamics Method ◽  
Growth Processes ◽  
Molecular Film ◽  
Dynamics Method

Ellipsometric Measurement of Bacterial Films at Metal-Electrolyte Interfaces

1998 ◽  
Vol 64 (10) ◽  
pp. 3690-3697 ◽  
Author(s):  
J. P. Busalmen ◽  
S. R. de Sánchez ◽  
D. J. Schiffrin
Keyword(s):  
Film Growth ◽  
Film Formation ◽  
High Sensitivity ◽  
Bacterial Attachment ◽  
Optical Measurements ◽  
Ellipsometric Measurement ◽  
Effective Medium Model ◽  
Bacterial Films ◽  
Bacterial Film

ABSTRACT Ellipsometric measurements were used to monitor the formation of a bacterial cell film on polarized metal surfaces (Al-brass and Ti). Under cathodic polarization bacterial attachment was measured from changes in the ellipsometric angles. These were fitted to an effective medium model for a nonabsorbing bacterial film with an effective refractive index (nf ) of 1.38 and a thickness (df ) of 160 ± 10 nm. From the optical measurements a surface coverage of 17% was estimated, in agreement with direct microscopic observations. The influence of bacteria on the formation of oxide films was monitored by ellipsometry following the film growth in situ. A strong inhibition of metal oxide film formation was observed, which was assigned to the decrease in oxygen concentration due to the presence of bacteria. It is shown that the irreversible adhesion of bacteria to the surface can be monitored ellipsometrically. Electrophoretic mobility is proposed as one of the factors determining bacterial attachment. The high sensitivity of ellipsometry and its usefulness for the determination of growth of interfacial bacterial films is demonstrated.

scholarly journals 2D Materials in Development of Electrochemical Point-of-Care Cancer Screening Devices

Micromachines ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 662 ◽  
Author(s):  
Mohsen Mohammadniaei ◽  
Huynh Vu Nguyen ◽  
My Van Tieu ◽  
Min-Ho Lee
Keyword(s):  
Cancer Screening ◽  
2D Materials ◽  
Point Of Care ◽  
Low Cost ◽  
Clinical Analysis ◽  
Cancer Diagnostics ◽  
Electrochemical Sensing ◽  
Screening Tools ◽  
Electrochemical Biosensors ◽  
2D Material

Effective cancer treatment requires early detection and monitoring the development progress in a simple and affordable manner. Point-of care (POC) screening can provide a portable and inexpensive tool for the end-users to conveniently operate test and screen their health conditions without the necessity of special skills. Electrochemical methods hold great potential for clinical analysis of variety of chemicals and substances as well as cancer biomarkers due to their low cost, high sensitivity, multiplex detection ability, and miniaturization aptitude. Advances in two-dimensional (2D) material-based electrochemical biosensors/sensors are accelerating the performance of conventional devices toward more practical approaches. Here, recent trends in the development of 2D material-based electrochemical biosensors/sensors, as the next generation of POC cancer screening tools, are summarized. Three cancer biomarker categories, including proteins, nucleic acids, and some small molecules, will be considered. Various 2D materials will be introduced and their biomedical applications and electrochemical properties will be given. The role of 2D materials in improving the performance of electrochemical sensing mechanisms as well as the pros and cons of current sensors as the prospective devices for POC screening will be emphasized. Finally, the future scopes of implementing 2D materials in electrochemical POC cancer diagnostics for the clinical translation will be discussed.

scholarly journals Supported and Suspended 2D Material-Based FET Biosensors

Electrochem ◽  
2020 ◽  
Vol 1 (3) ◽  
pp. 260-277 ◽  
Author(s):  
Nirul Masurkar ◽  
Sundeep Varma ◽  
Leela Mohana Reddy Arava
Keyword(s):  
Field Effect Transistor ◽  
Electrochemical Biosensor ◽  
2D Materials ◽  
Atomic Layer ◽  
Fabrication Technology ◽  
Semiconducting Materials ◽  
Biomolecule Detection ◽  
2D Material ◽  
2D Nanomaterials ◽  
Effect Transistor

Field Effect Transistor (FET)-based electrochemical biosensor is gaining a lot of interest due to its malleability with modern fabrication technology and the ease at which it can be integrated with modern digital electronics. To increase the sensitivity and response time of the FET-based biosensor, many semiconducting materials have been categorized, including 2 dimensional (2D) nanomaterials. These 2D materials are easy to fabricate, increase sensitivity due to the atomic layer, and are flexible for a range of biomolecule detection. Due to the atomic layer of 2D materials each device requires a supporting substrate to fabricate a biosensor. However, uneven morphology of supporting substrate leads to unreliable output from every device due to scattering effect. This review summarizes advances in 2D material-based electrochemical biosensors both in supporting and suspended configurations by using different atomic monolayer, and presents the challenges involved in supporting substrate-based 2D biosensors. In addition, we also point out the advantages of nanomaterials over bulk materials in the biosensor domain.

Multifield-tunable magneto-optical effects in electron- and hole-doped nitrogen–graphene crystals

2019 ◽  
Vol 7 (11) ◽  
pp. 3360-3368 ◽  
Author(s):  
Xiaodong Zhou ◽  
Fei Li ◽  
Yanxia Xing ◽  
Wanxiang Feng
Keyword(s):  
2D Materials ◽  
Optical Devices ◽  
Strain Fields ◽  
2D Material ◽  
Optical Effects ◽  
Faraday Effects

The magneto-optical effects play a prominent role in probing the exotic magnetism in 2D materials. Here, we present that the magneto-optical Kerr and Faraday effects in carrier-doped nitrogen–graphene crystals can be effectively mediated by electric, magnetic, and strain fields. Our results indicate that nitrogen–graphene crystals provide a novel 2D material platform for nano-spintronics and magneto-optical devices.

scholarly journals 2D material liquid crystals for optoelectronics and photonics

2017 ◽  
Vol 5 (43) ◽  
pp. 11185-11195 ◽  
Author(s):  
B. T. Hogan ◽  
E. Kovalska ◽  
M. F. Craciun ◽  
A. Baldycheva
Keyword(s):  
Liquid Crystals ◽  
Materials Science ◽  
2D Materials ◽  
2D Material

The merging of the materials science paradigms of liquid crystals and 2D materials promises superb new opportunities for the advancement of the fields of optoelectronics and photonics. In this review, we summarise the development and applications of 2D material liquid crystals for optoelectronics and photonics.

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