Interaction of Reactive Species Obtained by G-D Silane Decomposition with Si(111) and a-Si:H Surfaces

1987 ◽  
Vol 95 ◽  
Author(s):  
S. A. Cruz ◽  
V. M. Mendez-Rosales
Keyword(s):  
Potential Barrier ◽  
Surface Potential ◽  
Reactive Species ◽  
Interatomic Potentials ◽  
Average Surface ◽  
Thomas Fermi ◽  
First Case ◽  
Crystalline Surface ◽  
Total Interaction

AbstractWe calculate the average surface potential barrier for incorporation of H, Si, SiHb (n=1–4) into films of a-Si:H as well as crystalline Si(111) surfaces. In the first case a local amorphous configuration for the surface is employed through a representative cluster(Si29 H1 0 ) forming 5, 6, 7 Si atom rings. For the crystalline surface, several layers of Si atoms are considered. Pairwise superposition of combined Morse and Thomas-Fermi-Moliére interatomic potentials is assumed for the total interaction between the incoming species and the surface.

Evolution of surface potential barrier for negative-electron-affinity GaAs photocathodes

2009 ◽  
Vol 105 (1) ◽  
pp. 013714 ◽  
Author(s):  
Jijun Zou ◽  
Benkang Chang ◽  
Zhi Yang ◽  
Yijun Zhang ◽  
Jianliang Qiao
Keyword(s):  
Potential Barrier ◽  
Surface Potential ◽  
Electron Affinity ◽  
Negative Electron Affinity

The relationship between inner surface potential and electrokinetic potential from an experimental and theoretical point of view

2017 ◽  
Vol 14 (5) ◽  
pp. 295 ◽  
Author(s):  
Tajana Preočanin ◽  
Danijel Namjesnik ◽  
Matthew A. Brown ◽  
Johannes Lützenkirchen
Keyword(s):  
Surface Properties ◽  
Surface Potential ◽  
Single Particle ◽  
Surface Reactions ◽  
Solid Particles ◽  
Theoretical Point ◽  
Surface Characterisation ◽  
Layer Potential ◽  
Average Surface ◽  
Inner Surface

Environmental contextInterfacial properties of colloid and nanoparticles are directly related to the reactivity and surface densities of existing surface sites. Surface characterisation of particles provides only some kind of average surface properties. Analysis of well-defined monocrystal surfaces, which form the surface of the single particle, leads to a better understanding of surface reactions and mutual interactions of adjacent crystal planes on average surface properties. AbstractThe contact of small solid particles and macroscopic flat planes with aqueous electrolyte solutions results in the accumulation of ions at the interface and the formation of the electrical interfacial layer. Analysis of well-defined monocrystal surfaces, which are the building blocks of a single particle, leads to a better understanding of surface reactions and mutual interactions of adjacent crystal planes on average surface properties of particles. We analyse inner surface potential (obtained by single-crystal electrode) and zeta-potential data (obtained by streaming potential measurements) that were obtained on identical samples. Among the systems for which comparable surface and zetapotentials are available, measured inner surface potential data for sapphire (0001), haematite (0001) and rutile (110) show the expected behaviour based on the face-specific surface chemistry model, whereas the slopes for rutile (110) and quartz (0001) do not. Isoelectric points for sapphire (0001), haematite (0001) and rutile (100) are in conflict with the standard model that implies consistent behaviour of surface potential and diffuse layer potential. For the two former systems, previous results from the literature suggest that the charge of interfacial water can explain the discrepancy. The water layer could also play a role for quartz (0001), but in this case, the discrepancy would simply not be noticed, because both point of zero potential and isoelectric point are low. Along with data on silver halides, it can be concluded that six-ring water structures on solids may generate the electrokinetic behaviour that is typical of inert surfaces like Teflon.

Contactless electroreflectance studies of surface potential barrier for N- and Ga-face epilayers grown by molecular beam epitaxy

2013 ◽  
Vol 103 (5) ◽  
pp. 052107 ◽  
Author(s):  
R. Kudrawiec ◽  
L. Janicki ◽  
M. Gladysiewicz ◽  
J. Misiewicz ◽  
G. Cywinski ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Potential Barrier ◽  
Surface Potential ◽  
Molecular Beam

scholarly journals Charge Densities above Pulsar Polar Caps

2000 ◽  
Vol 177 ◽  
pp. 463-464
Author(s):  
A. Jessner ◽  
H. Lesch ◽  
Th. Kunzl
Keyword(s):  
Neutron Star ◽  
Electric Field ◽  
Work Function ◽  
Potential Barrier ◽  
Electric Fields ◽  
Surface Potential ◽  
Thermal Emission ◽  
Equilibrium Density ◽  
Charge Densities ◽  
Polar Caps

A simplified model provided the framework for our investigation into the distribution of energy and charge densities above the polar caps of a rotating neutron star. We assumed a neutron star withm= 1.4M⊙,r= 10km, dipolar field |B0| = 1012G,B||Ω and Ω = 2Π · (0.5s)−1. The effects of general relativity were disregarded. The induced accelerating electric fieldE||reachesE0= 2.5 · 1013V m−1at the surface near the magnetic poles. The current density along the field lines has an upper limitnGJ, when the electric field of the charged particle flow cancels the induced electric field: At the polesnGJ(r=rns,θ= 0) = 1.4 · 1017m−3.The work function(surface potential barrier)EWis approximated by the Fermi energyEFof magnetised matter. Following Abrahams and Shapiro (1992) one needs to revise the surface density from the canonical 1.4 · 108kg m−3down toρFe = 2.9 · 107kg m−3. Withwe obtain a value ofEF=Ew= 417eV. There are two relevant particle emission processes:Field (cold cathode) emissionby quantum-mechanical tunneling of charges through the surface potentialandthermal emissionwhich is a purely classical process. In strong electric fields it is enhanced by the lowering of the potential barrier due to the Schottky effect. The combined Dushman-Schottky equationwithtells us, thatat temperatures> 2 · 105K the the Goldreich-Julian current can be supplied thermal emission alone. The surface temperature however has a lower limit in the order of 105K due to the rotational braking. Therefore, in most cases a sufficient supply of charges for the Goldreich-Julian current is available and the electrical field accelerating the particles will be quenched as a result of their abundance. Otherwise a residual equilibrium electric field Eeqremains with:and hence the equilibrium density is:n=nfieid(Eeq,EW) +nDS(Eeq,EW,T) For a temperature just below the onset of thermal emission (T= 1.85 · 105K) the charge density is found to vary almost linearly with the work functionEWfor values ofEWbetween 0.3 and 2 keV. At the chosen value forEWof 417 eVthe residual electric field amounts to only 8.5% of the vacuum value. Even in the residual electric field the particles are rapidly accelerated to relativistic energies balanced by inverse Compton and curvature radiation losses.

Surface Charge Imaging in Semiconductor Wafers by Surface Photovoltage (SPV)

1992 ◽  
Vol 261 ◽  
Author(s):  
Piotr Edelman ◽  
Jacek Lagowski ◽  
Lubek Jastrzebski
Keyword(s):  
Surface Charge ◽  
Potential Barrier ◽  
Surface Potential ◽  
Surface Photovoltage ◽  
High Excitation ◽  
Wafer Scale ◽  
Contact Measurement

ABSTRACTWe present fast, wafer-scale imaging of the surface charge achieved via non-contact measurement of the surface potential barrier by surface photovoltage (SPV) under high excitation levels. The approach is capable of resolving surface charge differences as small as 108 q/cm2. Fundamentals of surface charge imaging are discussed, and the method is compared with standard SPV contamination mapping. Examples include problems relevant to silicon IC fabrication and surface charge maps of GaAs and InP.

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