What is photoconductivity process?
Photoconductivity is an optical and electrical phenomenon in which a material becomes more electrically conductive due to the absorption of electromagnetic radiation such as visible light, ultraviolet light, infrared light, or gamma radiation.
What is photoconductivity explain its working and applications?
A photoconductor or Photoconductivity is an electrical & optical phenomenon where a material turns into conductive more electrically because of the electromagnetic radiation absorption like infrared light, ultraviolet light, visible light, or gamma radiation.
Why CdS is used in photoconductivity?
A low resistivity and a high photosensitivity are required for photoconductive-sensor applications. The band gap of CdS is in the range of visible light and the photosensitivity in the visible range is very high for CdS films.
What is the cause of photoconductivity?
Photoconductivity arises from the electrons freed by the light and from a flow of positive charge as well. Electrons raised to the conduction band correspond to missing negative charges in the valence band, called “holes.” Both electrons and holes increase current flow when the semiconductor is illuminated.
Who discovered photoconductivity?
Willoughby Smith (6 April 1828, in Great Yarmouth, Norfolk – 17 July 1891, in Eastbourne, Sussex) was an English electrical engineer who discovered the photoconductivity of the element selenium. This discovery led to the invention of photoelectric cells, including those used in the earliest television systems.
What is photoconductivity explain principle and construction of a photovoltaic cell?
Photoconductive Cell Construction and Working – Light striking the surface of a material can provide sufficient energy to cause electrons within the material to break away from their atoms. Thus, free electrons and holes (charge carriers) are created within the material, and consequently its resistance is reduced.
What is photoconductivity physics?
The photoconductivity is an optical/electrical phenomenon in which a material becomes more electrically conductive due to the absorption of electromagnetic radiation (such as visible light, ultraviolet light, infrared light, or gamma radiation).
What is irradiance photoconductivity?
a) The photocurrent IPh as a function of voltage U at a constant irradiance Φ: The relation between the photocurrent IPh and the voltage U applied at a constant irradiance (constant angle α between the polarization planes of the filters), i.e. the current-voltage characteristics, is shown in Fig.
What is photoconductivity response time?
The reported photoconductivity response time as measured from photocurrent decay ranged from a few tens of nanoseconds to a few minutes (Misra et al., 1995; Kung et al., 1995; Binet et al., 1996a).
What is a photoconductive material?
Photoconductive materials are used in the manufacture of photoelectric devices. Typical photoconductive substances consist of germanium, gallium, selenium, or silicon with impurities, also known as dopants , added. Other common materials include metal oxides and sulfides.
What is a photoconductive cell?
Definition of photoconductive cell : a photoelectric cell utilizing photoconductivity (as in a layer of selenium) so that an increase in illumination causes a decrease in electrical resistance and permits the flow of a greater electrical current.
What is the working principle of photovoltaic cell?
The PV cell consists of one or two layers of a semi conducting material, usually silicon. When light shines on the cell it creates an electric field across the layers causing electricity to flow. The greater the intensity of the light, the greater the flow of electricity.