The Difference Between Intrinsic and Extrinsic Semiconductors
Introduction
Semiconductors are crucial components of modern electronic devices, enabling the flow of electrical current under specific conditions. There are two types of semiconductors: intrinsic and extrinsic. In this article, we will explore the differences between these two types and delve into their respective properties, examples, and uses.
What is an Intrinsic Semiconductor?
An intrinsic semiconductor, also known as an undoped semiconductor, is a semiconductor material with a pure crystal structure, containing only the atoms of the semiconductor element itself. It does not possess any impurities intentionally added to modify its electrical properties.
Examples of Intrinsic Semiconductors
Some common examples of intrinsic semiconductors include:
- Silicon (Si)
- Gallium arsenide (GaAs)
- Germanium (Ge)
Uses of Intrinsic Semiconductors
Intrinsic semiconductors are widely used in various applications, including:
- Solar cells
- Integrated circuits
- Light-emitting diodes (LEDs)
What is an Extrinsic Semiconductor?
An extrinsic semiconductor, also known as a doped semiconductor, is a semiconductor material that has been intentionally modified by adding impurities called dopants. These dopants alter the electrical properties of the semiconductor, enhancing its conductivity and modifying its behavior.
Examples of Extrinsic Semiconductors
Some common examples of extrinsic semiconductors include:
- N-type semiconductor (e.g., silicon doped with phosphorus)
- P-type semiconductor (e.g., silicon doped with boron)
Uses of Extrinsic Semiconductors
Extrinsic semiconductors find extensive applications in electronic devices such as:
- Transistors
- Diodes
- Solar cells
Differences Between Intrinsic and Extrinsic Semiconductors
| Difference Area | Intrinsic Semiconductor | Extrinsic Semiconductor |
|---|---|---|
| Composition | Pure semiconductor material | Impurities intentionally added |
| Electrical Conductivity | Low | High |
| Carrier Concentration | Intrinsic carrier concentration | Higher carrier concentration due to dopants |
| Doping | Not doped | Doped with specific impurities |
| Type of Charge Carriers | Equal number of electrons and holes | Excess of either electrons or holes depending on doping |
| Conductivity Type | Intrinsic (can act as both N-type or P-type) | Determined by the type of dopant (N-type or P-type) |
| Temperature Dependence | Higher temperature increases conductivity | Higher temperature decreases conductivity |
| Impurity Levels | No impurity levels in the energy bandgap | Impurity levels exist within the energy bandgap |
| Applications | Solar cells, integrated circuits, LEDs | Transistors, diodes, solar cells |
| Availability | Available as pure semiconductor materials | Produced by doping intrinsic semiconductors |
Conclusion
In summary, intrinsic semiconductors are pure semiconducting materials, while extrinsic semiconductors have intentional impurities incorporated into them. Extrinsic semiconductors exhibit higher electrical conductivity and are suitable for specific applications that require controlled charge carriers. On the other hand, intrinsic semiconductors have lower electrical conductivity and are more versatile in their functionality.
People Also Ask
Here are some common questions that readers might have regarding intrinsic and extrinsic semiconductors:
Q: How are dopants added to a semiconductor?
Dopants are usually introduced during the crystal growth process of semiconductor fabrication. Various techniques such as ion implantation and diffusion are utilized to incorporate the dopants into the semiconductor material.
Q: Can intrinsic semiconductors conduct electricity?
Yes, intrinsic semiconductors can conduct electricity, but their conductivity is relatively low compared to extrinsic semiconductors. The conductivity can be enhanced by the addition of dopants in extrinsic semiconductors.
Q: What determines the conductivity type of an extrinsic semiconductor?
The conductivity type of an extrinsic semiconductor is determined by the type of dopant added. Doping with impurities like phosphorus results in an N-type semiconductor, while doping with impurities like boron creates a P-type semiconductor.
Q: Can the conductivity of extrinsic semiconductors be modified?
Yes, the conductivity of extrinsic semiconductors can be modified by adjusting the doping concentration. Higher doping concentrations result in higher conductivity.
Q: Are intrinsic semiconductors widely used in electronic devices?
While intrinsic semiconductors are not as commonly used as extrinsic semiconductors, they play a critical role in various applications, particularly in the field of solar energy conversion.
