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Understanding Energy Bands in Semiconductors: Fermi Energy and Distribution of States

Dive into the world of energy bands in semiconductors, Fermi energy, and state distributions guided by quantum numbers. Learn about the critical Fermi energy location and its impact on material properties. Explore calculations of densities, intrinsic and extrinsic semiconductors, and the unique characteristics of conduction and valence bands. Discover the fascinating interplay between electrons, holes, and energy states in this comprehensive study.

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Understanding Energy Bands in Semiconductors: Fermi Energy and Distribution of States

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  1. Energy bands p & n semiconductors

  2. Periodic table is specified by quantum numbers Most common IV material

  3. Energy bands Conduction band Does not contain electrons Valence band May contain electrons Insulator Semiconductor Conductor

  4. Energy bands distribution There are no states in this region

  5. Distribution of states & electrons Are these states filled? Where is the Fermi energy?

  6. Fermi-Dirac distribution The location on an energy diagram of the Fermi energy is a critical parameter to define materials!

  7. Fermi energy Distribution of states & electronsFermi function T = 0° T > 0° . .

  8. Distribution of states & electronscalculation of densities -- intrinsic Upper limit is the top of the conduction band. Fermi function approaches 0. Fermi function approaches 1 Density of the electrons and holes

  9. Distribution of states & electronscalculation of densities small

  10. Distribution of states & electronscalculation of densities

  11. Distribution of states & electronscalculation of densities

  12. Distribution of states & electronscalculation of densities

  13. Distribution of states & electronscalculation of densities small

  14. Intrinsic semiconductor

  15. . . Intrinsic semiconductor

  16. Intrinsic semiconductorlocation of the Fermi energy Fermi energy is not exactly between the two energies.

  17. Typical numbers at 300° Kelvin

  18. 2.19(a) Determine the total number of energy states in silicon between Ec and Ec + BT at 300°.

  19. Periodic table is specified by quantum numbers Most common III & V compounds

  20. extrinsic semiconductor Electron Hole

  21. Acceptor energy extrinsic semiconductor p type material

  22. Donor energy extrinsic semiconductor n type material

  23. 2.19(b) Determine the total number of energy states in gallium arsenide between Ec and Ec + BT at 300°.

  24. Milwaukee Journal February, 2007

  25. A hydrogen atom lost its electron and went to the police station to file a missing electron report. He was questioned by the police: "Haven't you just misplaced it somewhere? Are you sure that your electron is really lost?""I'm positive." replied the atom.

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