Surface Potential: Measuring Confined Electrons & Holes

[sinayu71]

surface potential is defined as the electrostatic potential energy of a surface confined charges. By Kelvin probe microscope, the the surface potential can be measured and the variation from negative to positive can be seen at different region on the interface.
My question is: is it correct to say that the area with negative surface potential has already confined certain amount of electrons whereas the holes has been confined in some areas with positive surface potential?

 

[Modey3]

Hello,

Kelvin Probe Microscopes measure the "work function" of a materials surface. There are two ways (yielding two different resolutions, but let's forget about the tunneling method) to measure the work function of a surface: The lower resolution, phenomenologically classical method relies on the electrons overcoming the work function of a surface prior to conducting to the probe. The work function of a material will change with inhomogeneities in the material (different phases etc..). So back to your question. Remember that potentials are relative quantities. There isn't a "positive region" just a region where the work function is higher than the surrounding regions.
Hope this helps.

Regards
Modey3

 

[sinayu71]

Hi Modey 3: thank you for the answer.

For hole transport semiconductors, is that correct to say free holes traveling at interface will be easily trapped in the area with relatively higher workfunction ( also shows a relatively higher surface potential)?