Decomposition of the surface carbide on Ni(001) induced by copper adsorption and surface segregation of carbon

1991 ◽  
Vol 257 (1-3) ◽  
pp. L623-L627 ◽  
Author(s):  
H. Tochihara ◽  
A. Pomprasit ◽  
T. Kadowaki ◽  
S. Mizuno ◽  
H. Minagawa ◽  
...  
1991 ◽  
Vol 257 (1-3) ◽  
pp. L623-L627
Author(s):  
H. Tochihara ◽  
A. Pomprasit ◽  
T. Kadowaki ◽  
S. Mizuno ◽  
H. Minagawa ◽  
...  

Author(s):  
S. H. Chen

Sn has been used extensively as an n-type dopant in GaAs grown by molecular-beam epitaxy (MBE). The surface accumulation of Sn during the growth of Sn-doped GaAs has been observed by several investigators. It is still not clear whether the accumulation of Sn is a kinetically hindered process, as proposed first by Wood and Joyce, or surface segregation due to thermodynamic factors. The proposed donor-incorporation mechanisms were based on experimental results from such techniques as secondary ion mass spectrometry, Auger electron spectroscopy, and C-V measurements. In the present study, electron microscopy was used in combination with cross-section specimen preparation. The information on the morphology and microstructure of the surface accumulation can be obtained in a fine scale and may confirm several suggestions from indirect experimental evidence in the previous studies.


Author(s):  
P.-F. Staub ◽  
C. Bonnelle ◽  
F. Vergand ◽  
P. Jonnard

Characterizing dimensionally and chemically nanometric structures such as surface segregation or interface phases can be performed efficiently using electron probe (EP) techniques at very low excitation conditions, i.e. using small incident energies (0.5<E0<5 keV) and low incident overvoltages (1<U0<1.7). In such extreme conditions, classical analytical EP models are generally pushed to their validity limits in terms of accuracy and physical consistency, and Monte-Carlo simulations are not convenient solutions as routine tools, because of their cost in computing time. In this context, we have developed an intermediate procedure, called IntriX, in which the ionization depth distributions Φ(ρz) are numerically reconstructed by integration of basic macroscopic physical parameters describing the electron beam/matter interaction, all of them being available under pre-established analytical forms. IntriX’s procedure consists in dividing the ionization depth distribution into three separate contributions:


1994 ◽  
Vol 4 (12) ◽  
pp. 2231-2248 ◽  
Author(s):  
Mohan Sikka ◽  
Navjot Singh ◽  
Frank S. Bates ◽  
Alamgir Karim ◽  
Sushil Satija ◽  
...  

1981 ◽  
Vol 42 (7) ◽  
pp. 1025-1028 ◽  
Author(s):  
L. Schlapbach ◽  
C.R. Brundle

2002 ◽  
Vol 716 ◽  
Author(s):  
Victor I. Kol'dyaev

AbstractIt is accepted that surface Ge atoms are considered to be responsible for the surface B segregation process. A set of original experiments is carried out. A main observation from the B and Ge profiles grown at different conditions shows that at certain conditions B is taking initiative and determine the Ge surface segregation process. basic assumptions are suggested to self-consistently explain these original experimental features and what is observed in the literature. These results have a strong implication for modeling the B diffusion in Si1-xGex where the initial conditions should be formulated accounting for the correlation in B and Ge distribution. A new assumption for the initial condition to be “all B atoms are captured by Ge” is regarded as a right one implicating that there is no any transient diffusion representing the B capturing kinetics.


Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 399
Author(s):  
Mohammed Umar Abba ◽  
Hasfalina Che Man ◽  
Raba’ah Syahidah Azis ◽  
Aida Isma Idris ◽  
Muhammad Hazwan Hamzah ◽  
...  

High proportion of copper has become a global challenge owing to its negative impact on the environment and public health complications. The present study focuses on the fabrication of a polyvinylidene fluoride (PVDF)-polyvinyl pyrrolidone (PVP) fiber membrane incorporated with varying loading (0, 0.5, 1.0, 1.5, and 2.0 wt%) of titanium dioxide (TiO2) nanoparticles via phase inversion technique to achieve hydrophilicity along with high selectivity for copper removal. The developed fibers were characterized based on scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), permeability, porosity, zeta potential, and contact angle. The improved membrane (with 1.0 wt% TiO2) concentration recorded the maximum flux (223 L/m2·h) and copper rejection (98.18%). Similarly, 1.0 wt% concentration of TiO2 nanoparticles made the membrane matrix more hydrophilic with the least contact angle of 50.01°. The maximum copper adsorption capacity of 69.68 mg/g was attained at 1.0 wt% TiO2 concentration. The experimental data of adsorption capacity were best fitted to the Freundlich isotherm model with R2 value of 0.99573. The hybrid membrane developed in this study has considerably eliminated copper from leachate and the concentration of copper in the permeate was substantially reduced to 0.044 mg/L, which is below standard discharge threshold.


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