In Situ Observation of an Electrochemical Etching Reaction in Silicon

1995 ◽  
Vol 404 ◽  
Author(s):  
Frances M. Ross ◽  
Peter C. Searson
Keyword(s):  
Pore Formation ◽  
Electrochemical Etching ◽  
Ex Situ ◽  
In Situ Observation ◽  
Specimen Holder

AbstractWe describe a TEM specimen holder which has been designed and constructed in order to observe the process of electrochemical pore formation in silicon. The holder incorporates electrical feedthroughs and a sealed reservoir for the electrolyte and it accepts lithographically patterned silicon specimens. We present ex situ observations of progressive pore propagation and show dynamic, in situ observations of electrolyte movement within the pores.

In-Situ and Ex-Situ Studies of Silicon Interfaces and Nanostructures by Ellipsometry and Rds

1995 ◽  
Vol 406 ◽  
Author(s):  
U. Rossowl ◽  
L. Mantese ◽  
U. Frotscher ◽  
D. E. Aspnes ◽  
W. Richter
Keyword(s):  
Dielectric Function ◽  
Electrochemical Etching ◽  
Chemical Species ◽  
Ex Situ ◽  
Silicon Nanostructures ◽  
Interface Properties ◽  
Difference Spectroscopy ◽  
Reflectance Difference Spectroscopy ◽  
Modified Surfaces

AbstractWe report surface-induced optical anisotropy (SIOA) spectra and dielectric function data of vicinal Si(001) surfaces using reflectance-difference spectroscopy (RDS) and spectroscopic ellipsometry (SE). To find the main contributions of the optical response we took data for clean and by hydrogen, oxygen, and arsenic modified surfaces. The SIOA lineshapes, as measured by reflectance-difference (RD) spectroscopy, can be either derivative-like or similar to the dielectric function as measured by SE. The derivative-like spectra appear to be associated with step contributions while the dielectric-function-like behavior appears to arise from terrace dimers and/or changes in chemical species bonded to the steps. In addition, we present SE data of silicon nanostructures formed by electrochemical etching and find that their behavior is dominated by interface properties.

In-Situ Observation Of Aln Formation During Nitridation Of Sapphire By Ultrahigh Vacuum Transmission Electron Microscopy

1997 ◽  
Vol 482 ◽  
Author(s):  
M. Yeadon ◽  
M. T. Marshall ◽  
F. Hamdani ◽  
S. Pekin ◽  
H. Morkoc ◽  
...  
Keyword(s):  
Ultrahigh Vacuum ◽  
Ex Situ ◽  
In Situ Observation ◽  
Island Growth ◽  
Kinetic Measurements ◽  
Transmission Electron ◽  
Before And After ◽  
Subsequent Exposure ◽  
Diffraction Patterns

AbstractUsing a novel ultrahigh vacuum transmission electron microscope (UHV TEM) with insitu molecular beam epitaxy capability we have studied the nitridation of (0001) sapphire upon exposure to ammonia. Atomically flat sapphire surfaces for the experiments were obtained by high temperature annealing. Subsequent exposure to ammonia flow at 950°C led to the successful synthesis of epitaxial AIN; the films were characterized in-situ using TEM. Complimentary ex-situ atomic force microscopy (AFM) was also performed in order to characterize the surface morphology before and after nitridation.The experiments indicate that AIN grows by a 3D island growth mechanism. Electron diffraction patterns suggest an abrupt AIN/sapphire interface with no evidence of the formation of Al–O–N compounds. The rate limiting step in the nitridation reaction appears to be the diffusion of nitrogen and oxygen species between the free surface of the growing AIN film and the reaction interface. It is inferred from kinetic measurements that diffusion of these species occurs along the boundaries between coalescing AIN islands.

In-Situ Observation of Chemical Vapor Deposition of Thin Sige Films by Optical Reflection Interferometry

1994 ◽  
Vol 375 ◽  
Author(s):  
G. Ritter ◽  
B. Tillack ◽  
M. Weidner ◽  
F. G. Böbel ◽  
B. Hertel
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Ex Situ ◽  
In Situ Observation ◽  
Optical Reflection ◽  
Initial Stage

AbstractChemical Vapor Deposition of Si1-x Gex – films on Si (100) and of polycrystalline Si1-x Gex, layers on SiO2 – coated substrates have been performed at a pressure of 200 Pa in the temperature range of 500°C – 800°C, correspondingly. To observe the growth process and to characterize the growing thin films at deposition conditions an optical reflection interferometer (PYRITIERS) has been used. Comparing the data obtained at growth temperature with ex- situ measurements by spectroscopic ellipsometry the temperature dependence of optical constants of SiGe films have been evaluated. The reflectivity measurements during the deposition process allow to study the quality of the heteroepitaxial film, even in the initial stage of epitaxial growth.

Highly explosive basaltic eruptions: magma fragmentation induced by rapid crystallisation

2020 ◽  
Author(s):  
Fabio Arzilli ◽  
Giuseppe La Spina ◽  
Mike R. Burton ◽  
Margherita Polacci ◽  
Nolwenn Le Gall ◽  
...  
Keyword(s):  
Ex Situ ◽  
Explosive Eruptions ◽  
In Situ Observation ◽  
Sudden Increase ◽  
Crystallisation Kinetics ◽  
Magma Fragmentation ◽  
Crystallization Experiments ◽  
Basaltic Magmas ◽  
Kinetics Of

<p>Basaltic eruptions are the most common form of volcanism on Earth and planetary bodies. The low viscosity of basaltic magmas generally favours effusive and mildly explosive volcanic activity. Highly explosive basaltic eruptions occur less frequently and their eruption mechanism still remains subject to debate, with implications for the significant hazard associated with explosive basaltic volcanism. Particularly, highly explosive eruptions require magma fragmentation, yet it is unclear how basaltic magmas can reach the fragmentation threshold.</p><p>In volcanic conduits, the crystallisation kinetics of an ascending magma are driven by degassing and cooling. So far, the crystallisation kinetics of magmas have been estimated through ex situ crystallization experiments. However, this experimental approach induces underestimation of crystallization kinetics in silicate melts. The   crystallization experiments reported in this study were performed in situ at Diamond Light Source (experiment EE12392 at the I12 beamline), Harwell, UK, using basalt from the 2001 Etna eruption as the starting material. We combined a bespoke high-temperature environmental cell with fast synchrotron X-ray microtomography to image the evolution of crystallization in real time. After 4 hours at sub-liquidus conditions (1170 °C and 1150 °C) the system was perturbed through a rapid cooling (0.4 °C/s), inducing a sudden increase of undercooling. Our study reports the first in situ observation of exceptionally rapid plagioclase and clinopyroxene crystallisation in trachybasaltic magmas. We combine these constraints on crystallisation kinetics and viscosity evolution with a numerical conduit model to show that exceptionally rapid syn-eruptive crystallisation is the fundamental process required to trigger basaltic magma fragmentation under high strain rates. Our in situ experimental and natural observations combined with a numerical conduit model allow us to conclude that pre-eruptive temperatures <1,100°C can promote highly explosive basaltic eruptions, such as Plinian volcanism, in which fragmentation is induced by fast syn-eruptive crystal growth under high undercooling and high decompression rates. This implies that all basaltic systems on Earth have the potential to produce powerful explosive eruptions.</p>

Tip Treatment

2021 ◽  
pp. 343-358
Author(s):  
C. Julian Chen
Keyword(s):  
Tungsten Wire ◽  
High Field ◽  
Electrochemical Etching ◽  
Treatment Method ◽  
Ex Situ ◽  
Experimental Procedure ◽  
Treatment Methods ◽  
Spin Polarized ◽  
Afm Tips

This chapter discusses various methods for tip treatment. First, a general discussion about the experimental facts of STM and AFM tips is presented, which points to the subtleties and significance of the last few atoms at the tip apex. The standard method of making an STM tip is the electrochemical etching of a tungsten wire. The experimental procedure is described in detail. The study of the tip using field-ion microscopy is outlined. The tungsten tips freshly made from electrochemical etching often do not provide atomic resolution. Ex-situ and in-situ tip treatments are necessary. Several ex-situ tip treatment methods are described, inducing annealing, field evaporation, and annealing with a field. In-situ tip treatment method such as high-field treatment and controlled collision are described. Then, tip treatment for electrochemical STM is described. Tip treatment methods for spin-polarized STM are described. Finally, tip functionalization, especially with Xe atom and CO molecule, is described.

In-situ Observation of Pore Formation and Photoelectrochemical Etching in n-InP

2019 ◽  
Vol 6 (2) ◽  
pp. 331-343 ◽  
Author(s):  
Robert P. Lynch ◽  
Monika Dornhege ◽  
Pablo Sánchez Bodega ◽  
Harm Hinrich Rotermund ◽  
D. N. Buckley
Keyword(s):  
Pore Formation ◽  
In Situ Observation ◽  
Photoelectrochemical Etching

scholarly journals Direct Observation of Monolayer MoS2 Prepared by CVD Using In-Situ Differential Reflectance Spectroscopy

Nanomaterials ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1640 ◽  
Author(s):  
Yina Wang ◽  
Lei Zhang ◽  
Chenhui Su ◽  
Hang Xiao ◽  
Shanshan Lv ◽  
...  
Keyword(s):  
Growth Mechanism ◽  
Transition Metal Dichalcogenides ◽  
Chemical Vapor ◽  
Reflectance Spectroscopy ◽  
Ex Situ ◽  
In Situ Observation ◽  
Two Dimensional ◽  
Monolayer Mos2 ◽  
Metal Dichalcogenides

The in-situ observation is of great significance to the study of the growth mechanism and controllability of two-dimensional transition metal dichalcogenides (TMDCs). Here, the differential reflectance spectroscopy (DRS) was performed to monitor the growth of molybdenum disulfide (MoS2) on a SiO2/Si substrate prepared by chemical vapor deposition (CVD). A home-built in-situ DRS setup was applied to monitor the growth of MoS2 in-situ. The formation and evolution of monolayer MoS2 are revealed by differential reflectance (DR) spectra. The morphology, vibration mode, absorption characteristics and thickness of monolayer MoS2 have been confirmed by optical microscopy, Raman spectroscopy, ex-situ DR spectra, and atomic force microscopy (AFM) respectively. The results demonstrated that DRS was a powerful tool for in-situ observations and has great potential for growth mechanism and controllability of TMDCs prepared by CVD. To the best of the authors’ knowledge, it was the first report in which the CVD growth of two-dimensional TMDCs has been investigated in-situ by reflectance spectroscopy.

In Situ Observation of Ni-Ti Thin Film Growth by Synchrotron Radiation Scattering

2006 ◽  
Vol 514-516 ◽  
pp. 1588-1592
Author(s):  
Rui Miguel S. Martins ◽  
Francisco Manuel Braz Fernandes ◽  
Rui Jorge C. Silva ◽  
Manfred Beckers ◽  
Norbert Schell
Keyword(s):  
Film Growth ◽  
Large Angle ◽  
Ex Situ ◽  
In Situ Observation ◽  
Research Station ◽  
Scattering Geometry ◽  
Angle Scattering ◽  
In Situ Experiments ◽  
Materials Research

A sputter deposition chamber inserted into the six-circle Huber diffractometer of the materials research station of the ROssendorf BeamLine (ROBL-CRG) at ESRF allowed to perform in-situ experiments during film growth of Ni-Ti. It is equipped with Kapton windows for X-Ray Diffraction (XRD) and specular Reflectivity (XRR) measurements. By following in situ the evolution of the structure of the growing film, we reveal intermediate “states” which cannot be seen/revealed ex situ, because those states occurred only during the growth but were no longer visible after deposition. Vertical Bragg-Brentano large-angle scattering geometry was employed to study the different trends of structural transformations taking place during deposition. Ni-Ti films exhibiting a non-uniform phase content across the film thickness could be produced by varying the power of co-sputtering Ni-Ti plus Ti. A significant decrease of IB2{110}/IB2{200} was observed when a bias of -45 V was applied.

In-Situ Investigation of Cu-In-Se Reactions by Thin Film Calorimetry

1997 ◽  
Vol 485 ◽  
Author(s):  
D. Wolf ◽  
G. Müller
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Equilibrium Phase ◽  
Reaction Times ◽  
Practical Interest ◽  
Ex Situ ◽  
In Situ Observation ◽  
Flux Agent ◽  
In Situ Investigation

AbstractStudies of the reaction path during annealing of Cu-In-Se thin films for solar cell absorbers have been limited up to now to ex-situ analyses of the phase composition by X-Ray Diffraction (XRD) after processing by a specific temperature-time program. As an indirect method, the application of ex-situ XRD is not sufficient for the determination of reaction temperatures and reaction times for setting up a general model of CIS-formation.We show in this paper that the use of a calorimetric method (Thin Film Calorimetry, TFC) offers the advantage of a direct (in-situ) observation of thin film reactions. Special care is taken to use film thicknesses of practical interest for industrial application (1.5 – 3 μm). In a first step we show results of binary reactions in the Cu-In, In-Se and Cu-Se systems. Their knowledge is necessary for understanding the processes involved in the ternary CIS-layers. It turned out that thin Cu-In and Cu-Se films react already at room temperature and behave as predicted by the bulk equilibrium phase diagrams during heating. In-Se thin films show prominent exothermic reactions starting with the melting of In. The first phase to be formed is generally In2Se which is then converted to more Se-rich compounds. In ternary Cu-In-Se films (Cu/In = 1.00) we observe transitions of the Cu-Se-system which can be attributed to the decomposition of CuSe2 and CuSe. Consequences for the model of improved CIS-growth by a Cu-Se flux agent are discussed.

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