Semiconductors

Definition

Semiconductors are materials that have electrical conductivity between that of conductors, such as metals, and insulators, such as ceramics. They are the foundation of modern electronics, enabling the development of devices like transistors, integrated circuits, and microprocessors.

5 Must Know Facts For Your Next Test

1. Semiconductors exhibit a unique property called the Hall effect, which can be used to measure the strength of a magnetic field and the type of charge carriers present in the material.
2. The electrical resistance of a semiconductor material can be controlled by applying an external electric field, a property known as the field-effect, which is the basis for the operation of transistors.
3. Semiconductors can be classified as either intrinsic, where the material is pure, or extrinsic, where the material has been doped with impurities to modify its electrical properties.
4. The ability to precisely control the doping of semiconductors has enabled the fabrication of complex integrated circuits, which are the foundation of modern electronic devices.
5. Semiconductors exhibit a temperature-dependent electrical behavior, with their conductivity increasing as temperature rises, unlike metals, which typically have decreasing conductivity with increasing temperature.

Review Questions

• Explain how the unique electrical properties of semiconductors, such as their ability to be doped and their temperature-dependent behavior, enable the development of electronic devices like transistors and integrated circuits.
  • The ability to precisely control the electrical properties of semiconductors through doping is a key feature that enables the fabrication of advanced electronic devices. By introducing impurities into a semiconductor material, the concentration and type of charge carriers (electrons or holes) can be tuned, allowing for the creation of p-n junctions, the fundamental building blocks of diodes and transistors. Additionally, the temperature-dependent behavior of semiconductors, where their conductivity increases with rising temperature, is exploited in the design of various electronic components. This temperature-dependent behavior, combined with the ability to control charge carrier concentration, allows for the development of complex integrated circuits and microprocessors that are the backbone of modern electronics.
• Describe how the Hall effect, a unique property of semiconductors, can be utilized to measure the strength of a magnetic field and the type of charge carriers present in the material.
  • The Hall effect is a phenomenon observed in semiconductors where the application of a magnetic field perpendicular to the flow of electric current results in the generation of a transverse voltage. This voltage, known as the Hall voltage, is directly proportional to the strength of the magnetic field and the type of charge carriers (electrons or holes) present in the semiconductor material. By measuring the Hall voltage, it is possible to determine the strength of the magnetic field as well as the dominant type of charge carriers in the semiconductor. This property of semiconductors is extensively used in the design of magnetic field sensors, Hall effect devices, and other applications where the characterization of charge carrier behavior is crucial.
• Analyze how the unique electrical properties of semiconductors, such as their ability to be doped and their temperature-dependent behavior, contribute to the development of Ohm's law and the Hall effect, and how these principles are applied in the design and operation of electronic devices.
  • The electrical properties of semiconductors, particularly their ability to be doped and their temperature-dependent behavior, are fundamental to the understanding and application of Ohm's law and the Hall effect. Doping semiconductors with impurities allows for the precise control of charge carrier concentration, which is a key factor in determining the electrical resistance of the material, as described by Ohm's law. Additionally, the temperature-dependent behavior of semiconductors, where their conductivity increases with rising temperature, influences the relationship between voltage, current, and resistance, as outlined in Ohm's law. These properties enable the design and operation of a wide range of electronic devices, such as transistors, integrated circuits, and Hall effect sensors. By leveraging the unique characteristics of semiconductors, engineers can create highly efficient and versatile electronic components that are the foundation of modern technology.

Related terms

Doping: The process of intentionally introducing impurities into a semiconductor material to alter its electrical properties and improve its performance in electronic devices.

PN Junction: The interface between a p-type semiconductor and an n-type semiconductor, which is the fundamental building block of diodes, transistors, and other semiconductor devices.

Bandgap: The energy difference between the valence band and the conduction band in a semiconductor, which determines the material's electrical and optical properties.