scholarly journals Few-Layered mos2 Nanoparticles Covering Anatase tio2 Nanosheets: Comparison Between Ex-Situ and in-Situ Synthesis Approaches

Author(s):  
Rosangela Santalucia ◽  
Tiziano Vacca ◽  
Federico Cesano ◽  
Gianmario Martra ◽  
Francesco Pellegrino ◽  
...  

MoS2/TiO2 nanostructures made of MoS2 nanoparticles covering TiO2 nanosheets have been synthesized, either via ex-situ or in-situ approaches. Morphology and structure of MoS2/TiO2 hybrid nanostructures have been investigated and imaged by means of X-ray diffraction (XRD) analysis and high-resolution transmission electron microscopy (HRTEM), while the vibrational and the optical properties have been investigated by Raman, Fourier-transform infrared spectroscopy (FTIR) and UV−visible (UV-Vis) techniques. The different stacking degrees together with the size distribution of the MoS2 nanosheets, decorating the TiO2 nanosheets, have been carefully obtained from HRTEM images. The nature of the surface sites on the main exposed faces of both materials has been detected by means of in-situ FTIR spectra of adsorbed CO probe molecule. The results coming from the ex-situ and in-situ approaches will be compared, by highlighting the role of the synthesis processes in affecting morphology and structure of MoS2 nanosheets, including their curvature, surface defects, and stacking order. Some more, it will be shown that the in-situ approach is affecting the reactivity of the TiO2 nanosheets too, hence in turn affects the MoS2/TiO2 nanosheets interaction.

2020 ◽  
Vol 11 (1) ◽  
pp. 143
Author(s):  
Rosangela Santalucia ◽  
Tiziano Vacca ◽  
Federico Cesano ◽  
Gianmario Martra ◽  
Francesco Pellegrino ◽  
...  

MoS2/TiO2 nanostructures made of MoS2 nanoparticles covering TiO2 nanosheets have been synthesized, either via ex situ or in situ approaches. The morphology and structure of the MoS2/TiO2 hybrid nanostructures have been investigated and imaged by means of X-ray diffraction (XRD) analysis and high-resolution transmission electron microscopy (HRTEM), while the vibrational and optical properties have been investigated by Raman, Fourier-transform infrared (FTIR), and UV−visible (UV–vis) spectroscopies. Different stacking levels and MoS2 nanosheets distribution on TiO2 nanosheets have been carefully evaluated from HRTEM images. Surface sites on the main exposed faces of both materials have been established by means of in situ FTIR spectra of CO probe molecule adsorption. The results of the ex situ and in situ approaches are compared to underline the role of the synthesis processes affecting the morphology and structure of MoS2 nanosheets, such as curvature, surface defects, and stacking order. It will be shown that as a result of the in situ approach, the reactivity of the TiO2 nanosheets and hence, in turn, the MoS2–TiO2 nanosheets interaction are modified.


Author(s):  
D. Loretto ◽  
J. M. Gibson ◽  
S. M. Yalisove

The silicides CoSi2 and NiSi2 are both metallic with the fee flourite structure and lattice constants which are close to silicon (1.2% and 0.6% smaller at room temperature respectively) Consequently epitaxial cobalt and nickel disilicide can be grown on silicon. If these layers are formed by ultra high vacuum (UHV) deposition (also known as molecular beam epitaxy or MBE) their thickness can be controlled to within a few monolayers. Such ultrathin metal/silicon systems have many potential applications: for example electronic devices based on ballistic transport. They also provide a model system to study the properties of heterointerfaces. In this work we will discuss results obtained using in situ and ex situ transmission electron microscopy (TEM).In situ TEM is suited to the study of MBE growth for several reasons. It offers high spatial resolution and the ability to penetrate many monolayers of material. This is in contrast to the techniques which are usually employed for in situ measurements in MBE, for example low energy electron diffraction (LEED) and reflection high energy electron diffraction (RHEED), which are both sensitive to only a few monolayers at the surface.


Author(s):  
Hyoung H. Kang ◽  
Michael A. Gribelyuk ◽  
Oliver D. Patterson ◽  
Steven B. Herschbein ◽  
Corey Senowitz

Abstract Cross-sectional style transmission electron microscopy (TEM) sample preparation techniques by DualBeam (SEM/FIB) systems are widely used in both laboratory and manufacturing lines with either in-situ or ex-situ lift out methods. By contrast, however, the plan view TEM sample has only been prepared in the laboratory environment, and only after breaking the wafer. This paper introduces a novel methodology for in-line, plan view TEM sample preparation at the 300mm wafer level that does not require breaking the wafer. It also presents the benefit of the technique on electrically short defects. The methodology of thin lamella TEM sample preparation for plan view work in two different tool configurations is also presented. The detailed procedure of thin lamella sample preparation is also described. In-line, full wafer plan view (S)TEM provides a quick turn around solution for defect analysis in the manufacturing line.


2017 ◽  
Vol 19 (31) ◽  
pp. 20867-20880 ◽  
Author(s):  
David C. Bock ◽  
Christopher J. Pelliccione ◽  
Wei Zhang ◽  
Janis Timoshenko ◽  
K. W. Knehr ◽  
...  

Crystal and atomic structural changes of Fe3O4upon electrochemical (de)lithiation were determined.


2020 ◽  
Vol MA2020-02 (24) ◽  
pp. 1750-1750
Author(s):  
Andrea Quintero Colmenares ◽  
Patrice Gergaud ◽  
Jean-Michel Hartmann ◽  
Vincent Delaye ◽  
Nicolas Bernier ◽  
...  

Microscopy ◽  
2018 ◽  
Vol 67 (2) ◽  
pp. 112-120
Author(s):  
Hiroyasu Saka ◽  
Hiroyuki Iwata ◽  
Daisuke Kawaguchi

Abstract Radiation of a permeable laser beam into Si induces considerable modification of structures. Thermal stability of the laser-induced modified volumes (LIMV’s) was studied comprehensively by means of in situ and ex situ heating experiments using transmission electron microscopy. The behavior in the tail region of a LIMV can be understood by dislocation theory, while that of a void formed at the very focus of a laser beam cannot be understood easily.


MRS Advances ◽  
2016 ◽  
Vol 1 (12) ◽  
pp. 799-804 ◽  
Author(s):  
Eric D. Hintsala ◽  
Syed Asif ◽  
Douglas D. Stauffer

ABSTRACTMultilayered film stacks, with length scales less than 10 nm are commonly used in a variety of devices, but present significant challenges to mechanical testing and evaluation. This is due to property convolution of the different layers. Both the properties of the individual layers and the combined response of the film stack are important input for design optimization. Here, we present ex-situ nanoindentation of a film stack representative of a perpendicular magnetic recording (PMR) hard disc drive (HDD), with more than 10 layers. We then compare this with in-situ transmission electron microscopy indentation to visualize deformation of individual layers of the stack. The ex-situ testing reveals early plastic deformation, with an initially high contact pressure (13 GPa) and modulus ( >160 GPa), followed by significant softening (8 GPa contact pressure and 140 GPa modulus), then slight hardening to 9 GPa. From in-situ testing, it is revealed that the metallic layer directly under the diamond like carbon (DLC) contributes the majority of the deformation and plastic flow, which is in turn constrained by a metallic oxide.


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