Chemical and Biological Sensing Based on the Surface Photovoltage Measurement of the Si Surface Potential Barrier

2005 ◽  
Author(s):  
K. Nauka
Keyword(s):  
Potential Barrier ◽  
Surface Potential ◽  
Surface Photovoltage ◽  
Biological Sensing

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.

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

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.

Sign in / Sign up

Export Citation Format

Share Document