# [SCI] Semiconductor Physics
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**Semiconductor Physics** is the quantum mechanical understanding of materials with electrical conductivities intermediate between metals and insulators, which can be precisely controlled by doping, electric fields, and temperature.
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## Overview
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Semiconductors have a band gap — a range of energies forbidden to electrons. At room temperature, thermal excitation promotes electrons across the gap, making conduction possible. Doping (adding impurity atoms with extra or missing electrons) creates n-type or p-type semiconductors. The p-n junction (Shockley, 1949) rectifies current; the bipolar transistor (Bardeen, Brattain, Shockley, 1947) amplifies it.
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Silicon's native oxide (SiO₂) allows the MOSFET (1959), the basis of all modern microchips. Moore's Law — transistor density doubling every ~18 months — held from 1965 to ~2016, driving the digital revolution.
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## Key Figures & Recognition
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- **William Shockley** (1910–1989), **John Bardeen** (1908–1991), **Walter Brattain** (1902–1987): Transistor. **Nobel Prize 1956**.
- **Nick Holonyak Jr.** (1928–2022): LED (visible light), 1962.
- **Zhores Alferov** (1930–2019) & **Herbert Kroemer** (1928–): Semiconductor heterostructures. **Nobel Prize 2000**.
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## Seminal Papers
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- Bardeen, J. & Brattain, W. "The Transistor, A Semi-Conductor Triode." *Phys. Rev.* 74 (1948).
- [Shockley, W. "A Unipolar 'Field-Effect' Transistor." *Proc. IRE* 40 (1952)](https://doi.org/10.1109/JRPROC.1952.273964)
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# Parents
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* [SCI] Theory of Metals⏎