Real time in situ observation of (001)GaAs in OMCVD by reflectance difference spectroscopy

1992 ◽  
Vol 60-61 ◽  
pp. 534-543 ◽  
Author(s):  
Itaru Kamiya ◽  
D.E. Aspnes ◽  
H. Tanaka ◽  
L.T. Florez ◽  
E. Colas ◽  
...  
1988 ◽  
Vol 144 ◽  
Author(s):  
E. Colas ◽  
D.E. Aspnes ◽  
R. Bhat ◽  
A.A. Studna ◽  
M.A. Koza ◽  
...  

ABSTRACTReflectance-difference spectroscopy (RDS) is a recently developed optical technique that allows to monitor chemical and structural changes at a growing semiconductor surface, in-situ and in real-time. This technique was applied recently to organometallic chemical vapor deposition (OMCVD) on a [100] GaAs growth surface. The results show that submonolayer coverage of reacted species can be followed by this technique, which provided unique insights into the microscopic growth mechanisms. The time, temperature and pressure dependences of surface coverage show that OMCVD growth is controlled by two basic processes with distinct activation energies, i.e. reversible chemisorption (at -26 kcal/mole), and decomposition (at 39 kcal/mole) of trimethylgallium (TMG) at surface lattice sites. The importance of reversible chemisorption, which is of an excluded-volume type, due to the large size of the TMG molecule, had been overlooked until now in the literature, where only one activation energy was used to describe growth kinetics.


1998 ◽  
Vol 73 (26) ◽  
pp. 3857-3859 ◽  
Author(s):  
D. Stifter ◽  
M. Schmid ◽  
K. Hingerl ◽  
A. Bonanni ◽  
M. Garcia-Rocha ◽  
...  

Author(s):  
A. Lastras-Martinez ◽  
I. Lara-Velazquez ◽  
R.e. Balderas-Navarro ◽  
J. Ortega-Gallegos ◽  
L.f. Lastras-Martinez

2021 ◽  
Author(s):  
Jean-Michel Lellouche ◽  
Romain Bourdalle-Badie ◽  
Eric Greiner ◽  
Gilles Garric ◽  
Angelique Melet ◽  
...  

<p>The GLORYS12V1 system is a global eddy-resolving physical ocean and sea ice reanalysis at 1/12° resolution covering the 1993-present altimetry period, designed and implemented in the framework of the Copernicus Marine Environment Monitoring Service (CMEMS). All the essential ocean physical variables from this reanalysis are available with free access through the CMEMS data portal.</p><p>The GLORYS12V1 reanalysis is based on the current CMEMS global real-time forecasting system, apart from a few specificities that are detailed in this manuscript. The model component is the NEMO platform driven at the surface by atmospheric conditions from the ECMWF ERA-Interim reanalysis. Ocean observations are assimilated by means of a reduced-order Kalman filter. Along track altimeter sea level anomaly, satellite sea surface temperature and sea ice concentration data and in situ temperature and salinity (T/S) vertical profiles are jointly assimilated. A 3D-VAR scheme provides an additional correction for the slowly-evolving large-scale biases in temperature and salinity.</p><p>The performance of the reanalysis is first addressed in the space of the assimilated observations and shows a clear dependency on the time-dependent in situ observation system, which is intrinsic to most reanalyses. The general assessment of GLORYS12V1 highlights a level of performance at the state-of-the-art and the reliability of the system to correctly capture the main expected climatic interannual variability signals for ocean and sea ice, the general circulation and the inter-basins exchanges. In terms of trends, GLORYS12V1 shows a higher than observed  warming trend together with a lower than observed global mean sea level rise.</p><p>Comparisons made with an experiment carried out on the same platform without assimilation show the benefit of data assimilation in controlling water masses properties and their low frequency variability. Examination of the deep signals below 2000 m depth shows that the reanalysis does not suffer from artificial signals even in the pre-Argo period.</p><p>Moreover, GLORYS12V1 represents particularly well the small-scale variability of surface dynamics and compares well with independent (non-assimilated) data. Comparisons made with a twin experiment carried out at ¼° resolution allows characterizing and quantifying the strengthened contribution of the 1/12° resolution onto the downscaled dynamics.</p><p>In conclusion, GLORYS12V1 provides a reliable physical ocean state for climate variability and supports applications such as seasonal forecasts. In addition, this reanalysis has strong assets to serve regional applications and should provide relevant physical conditions for applications such as marine biogeochemistry. In a near future, GLORYS12V1 will be maintained to be as close as possible to real time and could therefore provide a relevant reference statistical framework for many operational applications.</p>


2017 ◽  
Vol 421 ◽  
pp. 608-610 ◽  
Author(s):  
A. Armenta-Franco ◽  
A. Lastras-Martínez ◽  
J. Ortega-Gallegos ◽  
D. Ariza-Flores ◽  
L.E. Guevara-Macías ◽  
...  

2018 ◽  
Vol 28 (42) ◽  
pp. 1804039 ◽  
Author(s):  
Tae Woong Kim ◽  
Naoyuki Shibayama ◽  
Ludmila Cojocaru ◽  
Satoshi Uchida ◽  
Takashi Kondo ◽  
...  

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