Processing of InP and GaAs Surfaces by Hydrogen and Oxygen Plasmas: In Situ Real Time Ellipsometric Monitoring

1996 ◽  
Vol 448 ◽  
Author(s):  
M. Losurdo ◽  
P. Capezzuto ◽  
G. Bruno
Keyword(s):  
Real Time ◽  
Uv Light ◽  
Native Oxide ◽  
Kinetics Of Oxidation ◽  
Hydrogen Plasmas ◽  
Defect Passivation ◽  
Hydrogen Exposure ◽  
Oxide Removal ◽  
Kinetics Of

AbstractRemote radiofrequency H2 and O2 plasma processing of InP and GaAs surfaces was investigated by in situ real time spectroscopic ellipsometry. Hydrogen plasmas were used for the native oxide removal and the defect passivation of III-V surfaces. The effect of hydrogen exposure time and of crystallographic orientation (GaAs (100), (110), (111)) on the chemistry and kinetics of oxygen removal and of phosphorus/arsenic depletion was investigated. Oxygen plasma anodization was used to grow oxide films on GaAs (100), (110) and (111) substrates. The effect of bias voltage and UV-light irradiation on the chemistry and kinetics of oxidation process and on the oxide properties was studied. The composition and morphology of the InP and GaAs surfaces resulting from these plasma treatments was described.

Probing the Dynamic Self-Assembly Behaviour of Photoswitchable Wormlike Micelles in Real Time

2018 ◽  
Author(s):  
Elaine A. Kelly ◽  
Judith E. Houston ◽  
Rachel Evans
Keyword(s):  
Real Time ◽  
Absorption Spectroscopy ◽  
Self Assembly ◽  
Uv Light ◽  
Wormlike Micelles ◽  
Tetraethylene Glycol ◽  
Light Illumination ◽  
First Time ◽  
Dependent Processes

Understanding the dynamic self-assembly behaviour of azobenzene photosurfactants (AzoPS) is crucial to advance their use in controlled release applications such as<i></i>drug delivery and micellar catalysis. Currently, their behaviour in the equilibrium <i>cis-</i>and <i>trans</i>-photostationary states is more widely understood than during the photoisomerisation process itself. Here, we investigate the time-dependent self-assembly of the different photoisomers of a model neutral AzoPS, <a>tetraethylene glycol mono(4′,4-octyloxy,octyl-azobenzene) </a>(C<sub>8</sub>AzoOC<sub>8</sub>E<sub>4</sub>) using small-angle neutron scattering (SANS). We show that the incorporation of <i>in-situ</i>UV-Vis absorption spectroscopy with SANS allows the scattering profile, and hence micelle shape, to be correlated with the extent of photoisomerisation in real-time. It was observed that C<sub>8</sub>AzoOC<sub>8</sub>E<sub>4</sub>could switch between wormlike micelles (<i>trans</i>native state) and fractal aggregates (under UV light), with changes in the self-assembled structure arising concurrently with changes in the absorption spectrum. Wormlike micelles could be recovered within 60 seconds of blue light illumination. To the best of our knowledge, this is the first time the degree of AzoPS photoisomerisation has been tracked <i>in</i><i>-situ</i>through combined UV-Vis absorption spectroscopy-SANS measurements. This technique could be widely used to gain mechanistic and kinetic insights into light-dependent processes that are reliant on self-assembly.

Understanding the phase formation kinetics of nano-crystalline kesterite deposited on mesoscopic scaffolds via in situ multi-wavelength Raman-monitored annealing

2016 ◽  
Vol 18 (42) ◽  
pp. 29435-29446 ◽  
Author(s):  
Zhuoran Wang ◽  
Samir Elouatik ◽  
George P. Demopoulos
Keyword(s):  
Real Time ◽  
Phase Formation ◽  
Formation Kinetics ◽  
Nano Crystalline ◽  
Multi Wavelength ◽  
Real Time Information ◽  
Kinetics Of ◽  
Time Information ◽  
Annealing Method

The in situ Raman monitored annealing method is developed in this work to provide real-time information on phase formation and crystallinity evolution of kesterite deposited on a TiO2 mesoscopic scaffold.

Kinetics of Ion-Exchange Reactions in Hybrid Organic–Inorganic Perovskite Thin Films Studied by In Situ Real-Time X-ray Scattering

2018 ◽  
Vol 9 (23) ◽  
pp. 6750-6754 ◽  
Author(s):  
Alessandro Greco ◽  
Alexander Hinderhofer ◽  
M. Ibrahim Dar ◽  
Neha Arora ◽  
Jan Hagenlocher ◽  
...  
Keyword(s):  
Thin Films ◽  
Ion Exchange ◽  
Real Time ◽  
Exchange Reactions ◽  
Inorganic Perovskite ◽  
X Ray ◽  
X Ray Scattering ◽  
Kinetics Of ◽  
Kinetics Of Ion Exchange

scholarly journals In situ wide-field visualization of palladium hydrogenation

2020 ◽  
Author(s):  
Chongjun Jin ◽  
Nicholas Fang ◽  
Xiaoyi She ◽  
Huifeng Du ◽  
Yang Shen ◽  
...  
Keyword(s):  
Real Time ◽  
Hydrogen Diffusion ◽  
Fast Response ◽  
Wide Field ◽  
Ion Diffusion ◽  
Optical Contrast ◽  
Self Organized ◽  
Transmission Electron ◽  
Kinetics Of

Abstract Visualizing hydrogenation processes in metals in real-time is important to various hydrogen-involved applications. However, observing hydrogen diffusion was limited by transmission electron microscopy, and the kinetics of hydrogenation in the interior of the metals was not reported. Here we proposed an optical microscopy-based visualization of palladium hydrogenation from diffusion surface to the interior by introducing a fast-response mechanical platform that transforms the hydrogen diffusion into self-organized ordered wrinkles with sharp optical contrast. This platform is an Au/Pd double layer on elastomer which results in directional hydrogenation from sidewall to the interior. The kinetics of hydrogenation in the interior of the palladium along the diffusion direction was monitored in real-time. This platform will enable in-situ visualization of atom/ion diffusion on metals that are crucial in energy storage and hydrogen detection.

Grain-Growth Kinetics of Nanocrystalline Iron Studied In Situ by Synchrotron Real-Time X-ray Diffraction

2000 ◽  
Vol 104 (11) ◽  
pp. 2467-2476 ◽  
Author(s):  
H. Natter ◽  
M. Schmelzer ◽  
M.-S Löffler ◽  
C. E. Krill ◽  
A. Fitch ◽  
...  
Keyword(s):  
Real Time ◽  
Grain Growth ◽  
Growth Kinetics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nanocrystalline Iron ◽  
Grain Growth Kinetics ◽  
Kinetics Of

Polysilicon Emitter Transistors Manufactured using a Novel Limited Reaction Processing System

1989 ◽  
Vol 146 ◽  
Author(s):  
Fred Ruddell ◽  
Colin Parkes ◽  
B Mervyn Armstrong ◽  
Harold S Gamble
Keyword(s):  
Thermal Processing ◽  
Rapid Thermal Processing ◽  
Processing System ◽  
Bipolar Transistors ◽  
Native Oxide ◽  
Plasma Oxidation ◽  
Oxide Removal ◽  
Polysilicon Emitter ◽  
Reaction Processing

ABSTRACTThis paper describes a LPCVD reactor which was developed for multiple sequential in-situ processing. The system is capable of rapid thermal processing in the presence of plasma stimulation and has been used for native oxide removal, plasma oxidation and silicon deposition. Polysilicon layers produced by the system are incorporated into N-P-N polysilicon emitter bipolar transistors. These devices fabricated using a sequential in-situ plasma clean-polysilicon deposition schedule exhibited uniform gains limited to that of long single crystal emitters. Devices with either plasma grown or native oxide layers below the polysilicon exhibited much higher gains. The suitability of the system for sequential and limited reaction processing has been established.

Probing the Dynamic Self-Assembly Behaviour of Photoswitchable Wormlike Micelles in Real Time

2018 ◽  
Author(s):  
Elaine A. Kelly ◽  
Judith E. Houston ◽  
Rachel Evans
Keyword(s):  
Real Time ◽  
Absorption Spectroscopy ◽  
Self Assembly ◽  
Uv Light ◽  
Wormlike Micelles ◽  
Tetraethylene Glycol ◽  
Light Illumination ◽  
First Time ◽  
Dependent Processes

Understanding the dynamic self-assembly behaviour of azobenzene photosurfactants (AzoPS) is crucial to advance their use in controlled release applications such as<i></i>drug delivery and micellar catalysis. Currently, their behaviour in the equilibrium <i>cis-</i>and <i>trans</i>-photostationary states is more widely understood than during the photoisomerisation process itself. Here, we investigate the time-dependent self-assembly of the different photoisomers of a model neutral AzoPS, <a>tetraethylene glycol mono(4′,4-octyloxy,octyl-azobenzene) </a>(C<sub>8</sub>AzoOC<sub>8</sub>E<sub>4</sub>) using small-angle neutron scattering (SANS). We show that the incorporation of <i>in-situ</i>UV-Vis absorption spectroscopy with SANS allows the scattering profile, and hence micelle shape, to be correlated with the extent of photoisomerisation in real-time. It was observed that C<sub>8</sub>AzoOC<sub>8</sub>E<sub>4</sub>could switch between wormlike micelles (<i>trans</i>native state) and fractal aggregates (under UV light), with changes in the self-assembled structure arising concurrently with changes in the absorption spectrum. Wormlike micelles could be recovered within 60 seconds of blue light illumination. To the best of our knowledge, this is the first time the degree of AzoPS photoisomerisation has been tracked <i>in</i><i>-situ</i>through combined UV-Vis absorption spectroscopy-SANS measurements. This technique could be widely used to gain mechanistic and kinetic insights into light-dependent processes that are reliant on self-assembly.

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