Intrinsic Semiconductor vs. Extrinsic Semiconductor — What's the Difference?
By Tayyaba Rehman & Fiza Rafique — Published on March 4, 2024
An intrinsic semiconductor is a pure form of semiconductor without any significant impurities, exhibiting poor conductivity at low temperatures. An extrinsic semiconductor is doped with impurities, enhancing its electrical conductivity significantly.
Difference Between Intrinsic Semiconductor and Extrinsic Semiconductor
Table of Contents
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Key Differences
Intrinsic semiconductors are made of a single material, typically silicon or germanium, that is highly pure. Their conductivity is governed by the movement of electrons and holes generated by thermal energy within the material. At low temperatures, intrinsic semiconductors behave almost like insulators due to the minimal charge carriers available. However, as the temperature increases, so does their conductivity, due to the increased generation of electron-hole pairs.
Extrinsic semiconductors, on the other hand, are intrinsic semiconductors that have been intentionally doped with a small amount of impurity atoms. These impurities introduce additional free charge carriers, either electrons (n-type) or holes (p-type), significantly enhancing the semiconductor's electrical conductivity even at lower temperatures. The doping process allows for the control over the electrical properties of the semiconductor, making extrinsic semiconductors highly useful in electronic devices.
The conductivity of intrinsic semiconductors is limited and depends on the thermal energy available to generate charge carriers. In contrast, extrinsic semiconductors have an increased number of charge carriers due to doping, leading to higher and more controllable conductivity. This characteristic makes extrinsic semiconductors essential for the fabrication of electronic components such as diodes, transistors, and integrated circuits.
The choice between using an intrinsic or extrinsic semiconductor depends on the intended application. Intrinsic semiconductors are valuable for applications requiring high purity and controlled electrical properties under varying temperatures. Extrinsic semiconductors are indispensable in the electronics industry, where specific conductivity levels are needed for device functionality.
In summary, while intrinsic semiconductors offer a baseline for understanding semiconductor behavior, extrinsic semiconductors provide the practical functionality required for modern electronics through the strategic introduction of impurities to control electrical properties.
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Comparison Chart
Material Purity
High purity, no intentional impurities
Doped with impurities to introduce extra charge carriers
Conductivity
Poor at low temperatures, improves with temperature
High conductivity at lower temperatures due to doping
Charge Carriers
Electrons and holes generated by thermal energy
Increased electrons (n-type) or holes (p-type) due to impurities
Temperature Dependence
Conductivity strongly dependent on temperature
Conductivity less dependent on temperature
Use in Electronics
Limited use in pure form
Widely used in devices like diodes and transistors
Compare with Definitions
Intrinsic Semiconductor
Conductivity increases with temperature.
Intrinsic germanium's conductivity rises significantly at higher temperatures.
Extrinsic Semiconductor
Semiconductor doped with impurities to enhance conductivity.
Silicon doped with phosphorus becomes an n-type extrinsic semiconductor.
Intrinsic Semiconductor
Used for understanding fundamental semiconductor physics.
Intrinsic semiconductors are essential for academic research.
Extrinsic Semiconductor
Offers controlled electrical properties.
The conductivity of extrinsic semiconductors can be precisely adjusted for electronic circuits.
Intrinsic Semiconductor
Behaves like an insulator at very low temperatures.
Intrinsic semiconductors demonstrate insulating properties near absolute zero.
Extrinsic Semiconductor
Essential for manufacturing electronic devices.
Extrinsic p-type semiconductors are used in making transistors.
Intrinsic Semiconductor
A pure semiconductor without doping.
Pure silicon crystals are used to study intrinsic semiconductor properties.
Extrinsic Semiconductor
Less temperature dependent for conductivity.
Extrinsic semiconductors maintain conductivity across a wider temperature range.
Intrinsic Semiconductor
Minimal free charge carriers at low temperature.
Intrinsic silicon acts as an insulator in cold conditions.
Extrinsic Semiconductor
Can be either n-type or p-type based on the dopant.
Boron-doped silicon creates a p-type extrinsic semiconductor.
Common Curiosities
How does doping affect a semiconductor?
Doping introduces additional charge carriers, significantly enhancing the semiconductor's electrical conductivity.
What is the difference between n-type and p-type extrinsic semiconductors?
N-type semiconductors have extra electrons as charge carriers, while p-type semiconductors have extra holes.
What makes a semiconductor intrinsic?
Its high purity and the absence of any significant impurities, relying solely on its own lattice structure for conductivity.
Why are intrinsic semiconductors not widely used in electronics?
Their conductivity is too dependent on temperature and generally too low for practical electronics applications without doping.
Can the conductivity of an extrinsic semiconductor be controlled?
Yes, by varying the amount and type of dopant, the electrical properties of extrinsic semiconductors can be precisely controlled.
What applications require intrinsic semiconductors?
Intrinsic semiconductors are mainly used in high-purity applications and research settings to study the fundamental properties of semiconductors.
Why is silicon commonly used in semiconductors?
Silicon is abundant, cost-effective, and has suitable electrical properties for doping, making it ideal for semiconductor devices.
What role does temperature play in the conductivity of intrinsic semiconductors?
Conductivity in intrinsic semiconductors increases with temperature due to the thermal generation of electron-hole pairs.
How are extrinsic semiconductors made?
By introducing specific impurities into the intrinsic semiconductor material through processes like diffusion or ion implantation.
How do extrinsic semiconductors contribute to electronic devices?
They are the foundation of nearly all electronic devices, providing the necessary conductivity and control for transistors, diodes, and integrated circuits.
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Written by
Tayyaba RehmanTayyaba Rehman is a distinguished writer, currently serving as a primary contributor to askdifference.com. As a researcher in semantics and etymology, Tayyaba's passion for the complexity of languages and their distinctions has found a perfect home on the platform. Tayyaba delves into the intricacies of language, distinguishing between commonly confused words and phrases, thereby providing clarity for readers worldwide.
Co-written by
Fiza RafiqueFiza Rafique is a skilled content writer at AskDifference.com, where she meticulously refines and enhances written pieces. Drawing from her vast editorial expertise, Fiza ensures clarity, accuracy, and precision in every article. Passionate about language, she continually seeks to elevate the quality of content for readers worldwide.
