Page 96 - Photonics Essentials an introduction with experiments
P. 96
Photoconductivity
90 Photonic Devices
Figure 5.12. Upon exposure to light, a photon is absorbed by the silver bromide, break-
ing the atomic bond and liberating an electron to the conduction band. The electron is
attracted to the silver sulfide because of the latter’s positive charge. The silver atom is
also mobile, but moves more slowly than the electron. Professor Shelly Errington of the
University of California at Santa Cruz drew this original illustration.
Figure 5.13. The camera shutter closes, ending exposure to light. This stops the gener-
ation of electrons and movement of silver atoms, ending the photoconductive process.
The internal physical structure of the silver bromide crystal has changed. Professor
Shelly Errington of the University of California at Santa Cruz drew this original illus-
tration.
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