1 electron = 1 photon?

Started Apr 12, 2013 | Discussions thread
PhotonTrapper Regular Member • Posts: 112
Re: 1 electron = 1 photon?

Jack Hogan wrote:

Simplifying, assuming a modern B&W silicon sensor without a CFA or other filtering and 100% fill factor, if we see one electron produced at the output of a photosite, can we assume that it was the result of one photon making it through to silicon - and that the probability of it dislodging an electron is the Charge Collection Efficiency (QE) of the semiconductor at the wavelength of the incoming photon, so that for a given Exposure

Electrons produced = photons(wavelength) hitting silicon * QE(wavelength)?

If the visible spectrum is between 380 and 760 nm, with a near-infrared photon having half the frequency/energy of a near-ultraviolet photon therefore burying deeper into silicon, does the following responsivity curve merely represent QE at various silicon depths?

Relative Number of electrons Generated as a Function of Impinging Photon Wavelength

Or could the fact that the responsivity at 760nm is more than 3 times that at 380nm mean that, for instance, sometimes 1 photon produces two electrons?


I think you would have to include interaction cross section coefficients into your model. They are not part of the charge collection efficiency but they are a function of the material (Z atomic number) and photon energy (i.e. wavelength).

Regarding double electron emission from on single photon, yes it is possible, but I don't think it has been done on CCD or CMOS material.


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