Semiconductors

Definition

Semiconductors are materials that have electrical conductivity between that of conductors and insulators, making them essential for modern electronics. Their unique properties allow them to control electrical current, which is fundamental for devices like transistors, diodes, and integrated circuits. Semiconductors can be intrinsic or extrinsic, depending on whether they are pure or doped with impurities to enhance their conductive properties.

5 Must Know Facts For Your Next Test

1. Semiconductors are typically made from elements like silicon or germanium, which are abundant and have suitable electronic properties.
2. The ability to manipulate the electrical properties of semiconductors through doping allows for the creation of p-type and n-type semiconductors, essential for diode and transistor function.
3. At absolute zero temperature, semiconductors act as insulators, but as temperature increases, they gain conductivity due to the excitation of electrons across the band gap.
4. The development of semiconductor technology has led to the miniaturization of electronic devices, paving the way for the modern computer age and mobile technology.
5. Scanning Probe Microscopy techniques like STM and AFM are vital for characterizing semiconductor surfaces at the nanoscale, providing insights into their structural and electronic properties.

Review Questions

• How does doping influence the electrical properties of semiconductors, and why is this important for their applications?
  • Doping significantly alters the electrical properties of semiconductors by introducing impurities that create either excess holes (p-type) or electrons (n-type). This manipulation is crucial because it allows for fine-tuning the conductivity levels needed in various electronic components. For example, transistors rely on precise doping to function effectively in amplifying or switching signals.
• Discuss how the band gap in semiconductors affects their behavior at different temperatures.
  • The band gap in semiconductors plays a critical role in determining their electrical behavior as temperature changes. At low temperatures, electrons lack sufficient energy to jump across the band gap, rendering the material an insulator. However, as temperature increases, some electrons gain enough energy to move into the conduction band, allowing for increased conductivity. This behavior is fundamental in applications like thermistors where temperature variations directly impact performance.
• Evaluate the impact of advancements in scanning probe microscopy techniques on semiconductor research and development.
  • Advancements in scanning probe microscopy techniques such as STM and AFM have profoundly impacted semiconductor research by enabling scientists to observe and manipulate materials at the atomic level. These techniques provide detailed information about surface topography, electronic structure, and defects within semiconductor materials. Such insights facilitate the development of new semiconductor devices with improved performance characteristics and contribute to innovations in nanotechnology and electronics.

Related terms

Doping:

The process of adding impurities to a semiconductor to change its electrical properties and enhance its conductivity.

Band Gap: The energy difference between the valence band and conduction band in a semiconductor, which determines its electrical conductivity.

Transistor: A semiconductor device used to amplify or switch electronic signals and electrical power, crucial for modern electronic circuits.