Analysis of Airborne Contamination on Transition Metal Dichalcogenides with Atomic Force Microscopy Revealing That Sulfur Is the Preferred Chalcogen Atom for Devices Made in Ambient Conditions

Abstract Transition metal dichalcogenides (TMDCs) have attracted significant attention for optoelectronic, photovoltaic and photoelectrochemical applications. The properties of TMDCs are highly dependent on the number of stacked atomic layers, which is usually counted post-fabrication, using a combination of optical methods and atomic force microscopy height measurements. Here, we use photoluminescence spectroscopy, Raman spectroscopy, and three different AFM methods to demonstrate significant discrepancies in height measurements of exfoliated MoSe2 flakes on SiO2 depending on the method used. We also highlight the often overlooked effect that electrostatic forces can be misleading when measuring the height of a MoSe2 flake using AFM.

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Conductive Atomic Force Microscopy of Semiconducting Transition Metal Dichalcogenides and Heterostructures

Nanomaterials ◽

10.3390/nano10040803 ◽

2020 ◽

Vol 10 (4) ◽

pp. 803 ◽

Cited By ~ 1

Author(s):

Filippo Giannazzo ◽

Emanuela Schilirò ◽

Giuseppe Greco ◽

Fabrizio Roccaforte

Keyword(s):

Atomic Force Microscopy ◽

Transition Metal ◽

Grain Boundaries ◽

Schottky Barrier ◽

Transition Metal Dichalcogenides ◽

Device Fabrication ◽

Conductive Atomic Force Microscopy ◽

Force Microscopy ◽

Atomic Force ◽

Metal Dichalcogenides

Semiconducting transition metal dichalcogenides (TMDs) are promising materials for future electronic and optoelectronic applications. However, their electronic properties are strongly affected by peculiar nanoscale defects/inhomogeneities (point or complex defects, thickness fluctuations, grain boundaries, etc.), which are intrinsic of these materials or introduced during device fabrication processes. This paper reviews recent applications of conductive atomic force microscopy (C-AFM) to the investigation of nanoscale transport properties in TMDs, discussing the implications of the local phenomena in the overall behavior of TMD-based devices. Nanoscale resolution current spectroscopy and mapping by C-AFM provided information on the Schottky barrier uniformity and shed light on the mechanisms responsible for the Fermi level pinning commonly observed at metal/TMD interfaces. Methods for nanoscale tailoring of the Schottky barrier in MoS2 for the realization of ambipolar transistors are also illustrated. Experiments on local conductivity mapping in monolayer MoS2 grown by chemical vapor deposition (CVD) on SiO2 substrates are discussed, providing a direct evidence of the resistance associated to the grain boundaries (GBs) between MoS2 domains. Finally, C-AFM provided an insight into the current transport phenomena in TMD-based heterostructures, including lateral heterojunctions observed within MoxW1–xSe2 alloys, and vertical heterostructures made by van der Waals stacking of different TMDs (e.g., MoS2/WSe2) or by CVD growth of TMDs on bulk semiconductors.

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Chromic Polydiacetylene Single Crystals: Atomic Force Microscopy Studies

MRS Proceedings ◽

10.1557/proc-413-445 ◽

1995 ◽

Vol 413 ◽

Author(s):

V. Shivshankar ◽

C. Sung ◽

J. Kumar ◽

S. K. Tripathy ◽

D. J. Sandman

Keyword(s):

Atomic Force Microscopy ◽

Surface Morphology ◽

Single Crystals ◽

Ambient Conditions ◽

Free Standing ◽

Force Microscopy ◽

Sensor Performance ◽

Atomic Force ◽

Variable Surface

ABSTRACTWe have studied the surface morphology of free standing single crystals of thermochromic polydiacetylenes (PDAs), namely, ETCD and IPUDO (respectively, the ethyl and isopropyl urethanes of 5,7-dodecadiyn-1,12-diol), by Atomic Force Microscopy (AFM) under ambient conditions. Micron scale as well as molecularly resolved images were obtained. The micron scale images indicate a variable surface, and the molecularly resolved images show a well defined 2-D lattice that is interpreted in terms of molecular models and known crystallographic data. Thereby information about surface morphology, which is crucial to potential optical device or chromic sensor performance is available. We also report the observation of a “macroscopic shattering” of the IPUDO monomer crystal during in-situ UV polymerization studies.

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Waterproof molecular monolayers stabilize 2D materials

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1909500116 ◽

2019 ◽

Vol 116 (42) ◽

pp. 20844-20849 ◽

Cited By ~ 4

Author(s):

Cong Su ◽

Zongyou Yin ◽

Qing-Bo Yan ◽

Zegao Wang ◽

Hongtao Lin ◽

...

Keyword(s):

Transition Metal ◽

Theoretical Analysis ◽

2D Materials ◽

Transition Metal Dichalcogenides ◽

Water Molecules ◽

Two Dimensional ◽

Ambient Conditions ◽

Molecular Monolayers ◽

Metal Dichalcogenides ◽

Van Der Waals Materials

Two-dimensional van der Waals materials have rich and unique functional properties, but many are susceptible to corrosion under ambient conditions. Here we show that linear alkylamines n-CmH2m+1NH2, with m = 4 through 11, are highly effective in protecting the optoelectronic properties of these materials, such as black phosphorus (BP) and transition-metal dichalcogenides (TMDs: WS2, 1T′-MoTe2, WTe2, WSe2, TaS2, and NbSe2). As a representative example, n-hexylamine (m = 6) can be applied in the form of thin molecular monolayers on BP flakes with less than 2-nm thickness and can prolong BP’s lifetime from a few hours to several weeks and even months in ambient environments. Characterizations combined with our theoretical analysis show that the thin monolayers selectively sift out water molecules, forming a drying layer to achieve the passivation of the protected 2D materials. The monolayer coating is also stable in air, H2 annealing, and organic solvents, but can be removed by certain organic acids.

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Direct Writing on Phosphate Glass Using Atomic Force Microscopy for Rapid Fabrication of Nanostructures

Volume 10: Micro- and Nano-Systems Engineering and Packaging ◽

10.1115/imece2016-67471 ◽

2016 ◽

Cited By ~ 1

Author(s):

Shama F. Barna ◽

Kyle E. Jacobs ◽

Glennys A. Mensing ◽

Placid M. Ferreira

Keyword(s):

Atomic Force Microscopy ◽

Ion Beam ◽

Soft Materials ◽

Constant Current ◽

Silver Nanostructures ◽

Direct Writing ◽

Ambient Conditions ◽

Commercial Development ◽

Force Microscopy ◽

Atomic Force

Rapid and cost effective fabrication of nanostructures is critical for experimental exploration and translation of results for commercial development. While conventional techniques such as E-beam or Focused Ion beam lithography serve some prototyping needs for nano-scale experimentations, cost and rate considerations prohibit use for manufacturing. Specialized lithographic processes [e.g. nanosphere lithography or interference lithography] are also powerful tools in creating nanostructures but provide limited shapes, positioning and size control of nanostructures. In this work, we demonstrated a liquid-free and mask-less electrochemical writing approach using atomic force microscopy (AFM) that is capable of making arbitrary shapes of silver nanostructures in seconds on a solid state super-ionic (AgI)x (AgPO3)(1−x) glass. Under ambient conditions. silver is extracted selectively on super-ionic (AgI)x (AgPO3)(1−x) glass surface by negatively biasing an AFM probe relative to an Ag film counter electrode. Both voltage controlled and current controlled writings demonstrated localized extraction of silver. The current controlled approach is shown to be the preferred writing approach to make repeatable and uniform patterns of silver on (AgI)x AgPO3(1−x), where x represents the mole fraction of AgI in the mixture and the control parameter that tunes the conductivity of the sample. We demonstrated current controlled printing of silver on two different compositions of the material (i.e. (AgI)0.125 (AgPO3 )0.875 and (AgI)0.25(AgPO3)0.75 ). Depending on the magnitude of the constant current and tip speed, line-width of the silver pattern can be ∼150 nm. The length of these patterns are limited to the maximum distance the tip can be moved using the AFM position controls. The substrate being optically transparent allows the use of this writing technique for rapid prototyping plasmonic devices. By using the patterned substrate as a template for replica molding of soft materials such as polydimethylsiloxane (PDMS), this writing technique can also be utilized for high throughput nano-channel fabrication in biofluidics and microfluidics devices.

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Analysis of the constant-excitation mode in frequency-modulation atomic force microscopy with active Q-Control applied in ambient conditions and liquids

Journal of Applied Physics ◽

10.1063/1.2817952 ◽

2007 ◽

Vol 102 (11) ◽

pp. 114310 ◽

Cited By ~ 16

Author(s):

D. Ebeling ◽

H. Hölscher

Keyword(s):

Atomic Force Microscopy ◽

Frequency Modulation ◽

Ambient Conditions ◽

Excitation Mode ◽

Force Microscopy ◽

Atomic Force

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(Invited) Electrical Atomic Force Microscopy for 2D Transition Metal Dichalcogenide Materials

ECS Meeting Abstracts ◽

10.1149/ma2017-01/16/997 ◽

2017 ◽

Keyword(s):

Atomic Force Microscopy ◽

Transition Metal ◽

Transition Metal Dichalcogenide ◽

Force Microscopy ◽

Atomic Force

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Atomic Force Microscopy in Microbiology: New Structural and Functional Insights into the Microbial Cell Surface

mBio ◽

10.1128/mbio.01363-14 ◽

2014 ◽

Vol 5 (4) ◽

Cited By ~ 92

Author(s):

Yves F. Dufrêne

Keyword(s):

Atomic Force Microscopy ◽

Cell Surface ◽

Cell Surface Molecules ◽

Microbial Cells ◽

Force Microscopy ◽

Surface Molecules ◽

Atomic Force ◽

Important Research Topic ◽

Sense And Respond ◽

Made In

ABSTRACT Microbial cells sense and respond to their environment using their surface constituents. Therefore, understanding the assembly and biophysical properties of cell surface molecules is an important research topic. With its ability to observe living microbial cells at nanometer resolution and to manipulate single-cell surface molecules, atomic force microscopy (AFM) has emerged as a powerful tool in microbiology. Here, we survey major breakthroughs made in cell surface microbiology using AFM techniques, emphasizing the most recent structural and functional insights.

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AFM Study of Untreated and Treated Fibers of Mongolian Goat Cashmere

Materials Science Forum ◽

10.4028/www.scientific.net/msf.610-613.175 ◽

2009 ◽

Vol 610-613 ◽

pp. 175-178 ◽

Cited By ~ 3

Author(s):

Namsrai Javkhlantugs ◽

Enkhbaatar Ankhbayar ◽

Khishigjargal Tegshjargal ◽

Damdin Enkhjargal ◽

Chimed Ganzorig

Keyword(s):

Surface Roughness ◽

Atomic Force Microscopy ◽

Fine Structure ◽

Ambient Conditions ◽

Bleaching Process ◽

Surface Change ◽

Force Microscopy ◽

Atomic Force ◽

Before And After ◽

The Difference

The morphological surface change of untreated and treated fibers of the Mongolian goat cashmere was investigated by atomic force microscopy (AFM) at ambient conditions. The cuticle scale heights of the Mongolian goat cashmere fibers were measured by the AFM for the fibers before and after treatment. The experimental results showed that the difference between the fine structure of the cuticle and surface roughness of untreated and treated fibers. We found that the surface morphological change of the cashmere fibers was strongly degraded after the bleaching process.

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