Semiconductor physics is a foundational pillar of modern electronics. Semiconductors are materials whose electrical conductivity lies between that of conductors (like copper) and insulators (like glass).

What Makes a Material a Semiconductor?

A semiconductor, such as silicon, has a unique band structure. At absolute zero, its valence band is full, and the conduction band is empty. However, the energy gap (band gap) between them is small enough that thermal energy at room temperature can excite electrons from the valence band into the conduction band, allowing electricity to flow.

Intrinsic and Extrinsic Semiconductors

• Intrinsic semiconductors are pure materials like silicon or germanium.
• Extrinsic semiconductors are doped with other atoms to increase conductivity:
  • N-type: More electrons (negative charge carriers) are introduced.
  • P-type: More holes (positive charge carriers) are introduced.

Applications

Semiconductors are used to make diodes, transistors, solar cells, and integrated circuits—the building blocks of computers and modern electronic devices.

Conclusion

Understanding semiconductor physics allows us to engineer the electronic world around us, from smartphones to solar panels.

Happy learning!