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Lecture

Semiconductor Detectors: Principles and Applications

In course

PHYS-452: Radiation detection

The course presents the detection of ionizing radiation in the keV and MeV energy ranges. Physical processes of radiation/matter interaction are introduced. All steps of detection are covered, as well as detectors, instrumentations and measurements methods ...

Description

This lecture covers the history and principles of semiconductor detectors for radiation detection, including the electronic band structure, charge carrier concentration, doping, p-n junctions, and detection chain. It explains the operation of intrinsic and extrinsic semiconductors, the impact of temperature on charge mobility, and the role of energy bands in semiconductors. The lecture also discusses the importance of cooling elemental crystals, the effects of doping on crystal conductivity, and the function of p-n junctions in detecting ionizing radiation.

Instructor

Vincent Pierre Lamirand

After a PhD on the measurement of (p,n) reactions cross sections on small accelerators (IRSN, France), I have worked on the development of neutron detectors and measurement methods for reactor physics (CEA, France). I am part of the LRS staff since October 2014.

Official source

Ontological neighbourhood

Physics

Condensed matter physics: Solid-state physics

Related concepts (32)

Valence and conduction bands

In solid-state physics, the valence band and conduction band are the bands closest to the Fermi level, and thus determine the electrical conductivity of the solid. In nonmetals, the valence band is the highest range of electron energies in which electrons are normally present at absolute zero temperature, while the conduction band is the lowest range of vacant electronic states. On a graph of the electronic band structure of a semiconducting material, the valence band is located below the Fermi level, while the conduction band is located above it.

Doping (semiconductor)

In semiconductor production, doping is the intentional introduction of impurities into an intrinsic semiconductor for the purpose of modulating its electrical, optical and structural properties. The doped material is referred to as an extrinsic semiconductor. Small numbers of dopant atoms can change the ability of a semiconductor to conduct electricity. When on the order of one dopant atom is added per 100 million atoms, the doping is said to be low or light.

Depletion region

In semiconductor physics, the depletion region, also called depletion layer, depletion zone, junction region, space charge region or space charge layer, is an insulating region within a conductive, doped semiconductor material where the mobile charge carriers have been diffused away, or have been forced away by an electric field. The only elements left in the depletion region are ionized donor or acceptor impurities. This region of uncovered positive and negative ions is called the depletion region due to the depletion of carriers in this region, leaving none to carry a current.

Band diagram

In solid-state physics of semiconductors, a band diagram is a diagram plotting various key electron energy levels (Fermi level and nearby energy band edges) as a function of some spatial dimension, which is often denoted x. These diagrams help to explain the operation of many kinds of semiconductor devices and to visualize how bands change with position (band bending). The bands may be coloured to distinguish level filling. A band diagram should not be confused with a band structure plot.

Semiconductor

A semiconductor is a material which has an electrical conductivity value falling between that of a conductor, such as copper, and an insulator, such as glass. Its resistivity falls as its temperature rises; metals behave in the opposite way. Its conducting properties may be altered in useful ways by introducing impurities ("doping") into the crystal structure. When two differently doped regions exist in the same crystal, a semiconductor junction is created.

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Covers the behavior of semiconductors, including intrinsic and extrinsic properties, doping, charge carriers, band bending, and p-n junction formation.

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Explores density of states in semiconductor devices, covering electron gas, energy bands, Fermi-Dirac distribution, and band structures.

Semiconductor Physics: Transistors and Diodes