Surface photovoltage, Space charge and Point charges

In summary, the surface photovoltage effect is the change in potential at the surface of a semiconductor when it is illuminated due to the creation of hole-electron pairs. This effect is caused by the presence of defects in the depletion regions near the surface, which create a built-in voltage and potential. In the case of metal nano-particles embedded within two organic semiconductors, if they are confined to a thin layer, this could potentially create a photovoltage across the interface when exposed to light. It is unclear whether this would occur in an infinite or finite square lattice.
  • #1
arrektor
15
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The surface photovoltage effect suggests that the potential at the surface of a semiconductor will change when it is illuminated since hole-electron pairs are created.

The regions near the surface (depletion regions) contains defects that create a built-in voltage and built-in potential and the mobile carriers are emptied from this region (creates a "band-bending").

I am thinking about the situation where metal nano-particles are embeeded within two semiconductors (organic). If these nanoparticles are restricted within a thin layer, would this create a photovoltage across that interface when light hits this system?
 
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  • #2
is it for an infinite or finite square lattice?
 

1. What is Surface Photovoltage?

Surface photovoltage (SPV) is a phenomenon that occurs when light is incident on a material surface, resulting in the creation of a built-in voltage. This voltage is caused by the separation of photogenerated electron-hole pairs at the surface, creating a space charge region that produces an electric field. The magnitude of the SPV depends on factors such as the material properties, light intensity, and wavelength.

2. What is Space Charge?

Space charge is the accumulation of electric charges in a region of a material, typically at a boundary or interface. In the context of SPV, the space charge is created by the separation of photogenerated electron-hole pairs, resulting in an electric field that can affect the properties of the material. Space charge can also occur in other situations, such as in a semiconductor device or in a plasma.

3. How does Surface Photovoltage affect material properties?

Surface photovoltage can affect material properties in several ways. The built-in electric field created by the space charge can alter the band structure and energy levels of the material, leading to changes in its electrical and optical properties. Additionally, the presence of space charge can affect charge carrier mobility and recombination rates, which can impact the material's performance in electronic and optoelectronic devices.

4. What is the difference between Space Charge and Point Charges?

Space charge and point charges are both related to the accumulation of electric charges, but there are some key differences between them. Space charge refers to the accumulation of charges in a region of a material, whereas point charges refer to discrete, localized charges. Additionally, space charge is typically caused by the separation of electron-hole pairs, while point charges can be introduced from external sources or through chemical processes.

5. How is Surface Photovoltage measured?

Surface photovoltage can be measured using various techniques, such as Kelvin probe force microscopy, surface photovoltage spectroscopy, or capacitance-voltage measurements. These methods involve applying a small voltage or electric field to the material surface and measuring the resulting changes in the surface potential or capacitance. These measurements can provide valuable information about the material's properties and the effects of space charge on its performance.

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