Semiconductors

Definition

Semiconductors are materials that have electrical conductivity between that of a conductor and an insulator. They play a critical role in electronics, as their conductivity can be altered by temperature, impurities, or electric fields, making them essential for devices like diodes, transistors, and solar cells.

5 Must Know Facts For Your Next Test

1. Semiconductors can exist in different crystal structures, such as diamond cubic in silicon and zinc blende in gallium arsenide, affecting their electronic properties.
2. Point defects like vacancies or interstitials in semiconductors can significantly influence their electrical performance and are essential in understanding how materials behave under different conditions.
3. The properties of semiconductors can be fine-tuned through doping techniques, allowing engineers to design materials with specific conductivity levels for various applications.
4. Temperature changes can have a notable effect on the conductivity of semiconductors, leading to increased electron mobility at higher temperatures.
5. Semiconductors form the backbone of modern electronics, enabling advancements in computing, telecommunications, and renewable energy technologies.

Review Questions

• How do different crystal structures affect the properties of semiconductors?
  • Different crystal structures of semiconductors impact their electronic properties by altering factors such as band gap energy and electron mobility. For instance, silicon has a diamond cubic structure which provides it with a specific band gap that makes it suitable for various electronic applications. On the other hand, materials like gallium arsenide, with a zinc blende structure, exhibit different conductive behaviors due to their unique arrangement of atoms. Understanding these structural differences is crucial when selecting materials for specific electronic functions.
• In what ways do point defects influence the performance of semiconductors?
  • Point defects such as vacancies and interstitials play a significant role in determining the electrical performance of semiconductors. These defects can disrupt the regular lattice structure, leading to changes in carrier concentration and mobility. For example, an increased number of vacancies can create additional energy levels within the band gap that may trap charge carriers, while interstitial defects can introduce localized states that affect conductivity. Therefore, controlling point defects is vital for optimizing semiconductor functionality in devices.
• Evaluate the relationship between doping and the functionality of semiconductors in electronic devices.
  • Doping is crucial for tailoring the electrical properties of semiconductors to enhance their functionality in electronic devices. By introducing specific impurities into a semiconductor material, it can be transformed into p-type or n-type, thereby enabling the formation of P-N junctions essential for diodes and transistors. The level and type of doping determine how effectively a semiconductor will conduct electricity and respond to external signals, making it possible to engineer devices that meet precise performance requirements. This manipulation of semiconductor behavior is foundational to modern electronics and technology.

Related terms

Doping: The process of adding impurities to a semiconductor to change its electrical properties, enhancing its conductivity.

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

P-N Junction: A junction formed by joining p-type and n-type semiconductors, crucial for the operation of many electronic devices such as diodes and transistors.