Unformatted text preview: o the sensitivity of photodiodes
when receiving light emissions. 190 © Festo Didactic GmbH & Co. KG • FP 1110 11. Physical fundamentals Luminescent diodes represent a relatively small spectral width of the emitted light,
which is generally between 30 – 140 nm (spectral halfwidth), see Fig. 11.4.5. 100
Rel. radiant intensity 1
40 20 0
Wavelength 1000 nm 1050 Spectral halfwidth (1) Fig. 11.4.5: Emission spectrum of a GaAs-LED Photodiodes Photodiodes are semi-conductor components which are based on the principle of
single-crystaline silicone or germanium. They are constructed in the same way as
ordinary semiconductor diodes and have a barrier layer which is however very
closely arranged underneath the crystal surface. If the diode is exposed to light
emission, then the photons penetrating the crystal (quantum of the optical
radiation) are absorbed and electrical charge carrier pairs are created. This effect is
known as the photoelectric effect. The charge carrier pairs are separated in the
barrier layer and an electrical current is created, i.e. the photoc...
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This note was uploaded on 11/01/2012 for the course CHEMICAL 102 taught by Professor Jamesrodriguez during the Spring '12 term at Universidad Politécnica de Cartagena.
- Spring '12