Optoelectronics

Photoconductivity – Definition, Working and its Applications: Photoconductivity – When excess electrons and holes are produced in a semiconductor, there is a corresponding increase in conductivity of a sample as indicated by the following equation Conductivity of semiconductor, The above equation is obtained from Eqs. (6.48) and (6.59). When the excess carriers in a semiconductor …

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Luminescence – Definition and Types: When a system absorbs energy in some form or other, it may be partly re-emitted as radiation. This phenomenon is called luminescence. Luminescence may occur in solids (crystals or glasses) as well as in liquids and gases. The mechanism of the process by which luminescence is caused varies from comparatively …

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Photon Absorption Coefficient: Photon Absorption Coefficient – When light falls on a semiconductor, the photons may be absorbed or they may propagate through the semiconductor depending on the photon energy (E) and the band gap energy EG. Where the photon energy is less than EG, the photons are not readily absorbed and the light is …

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Optical Absorption in Electronics: As discussed in Art. 25.3, light waves can be treated as particles, which are referred to as photons. The energy of a photon is E = hf where h is Plank’s constant and f is the frequency. Wavelength and energy can be related by where E is the photon energy in …

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What is Wave Particle Duality? Since waves exhibit particle-like behavior, then the particles also should exhibit wave—like properties. This theory (de Broglie) is based on the existence of a wave particle duality principle. The momentum of a photon is given as where λ is the wavelength of the light wave. Then, de Broglie hypothesized that …

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What is Photoelectric Effect?: When monochromatic light is incident on a clean surface of a material, then under certain conditions, electrons, also called photoelectrons, are emitted from the surface. The electrons in the metal absorb energy from the light, and some of the electrons receive sufficient energy to be ejected from the metal surface into …

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