Intrinsic vs. Extrinsic Semiconductors: Key Differences

semiconductor
intrinsic
extrinsic
doping
charge carrier

This article explains the key differences between intrinsic and extrinsic semiconductors. Let’s dive in!

What is a Semiconductor?

A semiconductor is a crucial component in modern electronics, possessing an electrical conductivity that falls between highly conductive metals and insulating materials. Think of it as a “Goldilocks” material – not too conductive, not too resistive, but just right!

Here’s a breakdown of key semiconductor characteristics:

  • Conductivity: Their resistivity lies between conductors and insulators.
  • Temperature Coefficient: They exhibit a negative temperature coefficient of resistance, meaning their conductivity increases as temperature rises.
  • Impurity Sensitivity: Their conductivity is significantly affected by the presence of impurities within the crystal lattice.

Semiconductors are fundamental to a vast array of solid-state devices, including transistors, integrated circuits (ICs), diodes, photodiodes, and LEDs. Common semiconductor materials include Germanium and Silicon.

More semiconductor characteristics:

  • Crystalline Structure: Semiconductors possess an organized, crystalline structure at the atomic level.
  • Light Sensitivity: Their conductivity is dramatically influenced by light rays of high intensity (ultraviolet and infrared).
  • Temperature Dependence: Conductivity changes based on temperature variations.

Intrinsic Semiconductors: The Pure Form

An intrinsic semiconductor is simply a semiconductor material in its absolutely pure form. It contains no significant impurities.

Extrinsic Semiconductors: Enhanced with Impurities

An extrinsic semiconductor, on the other hand, is a semiconductor material to which other elements have been intentionally added. This process, known as doping, alters the semiconductor’s electrical properties. Examples of extrinsic semiconductors include N-type and P-type materials.

P-Type Material: Adding Trivalent Elements

P-type material is created when a trivalent element (an element with three valence electrons, such as Indium or Gallium) is added to a tetravalent semiconductor (like Germanium or Silicon). This results in a “deficit” of electrons – essentially, “holes” – for each impurity atom. These holes act as positive charge carriers.

N-Type Material: Adding Pentavalent Elements

N-type material is created when a pentavalent element (an element with five valence electrons, like Arsenic or Antimony) is added to a tetravalent semiconductor. This creates a surplus of electrons provided by each impurity atom. These excess electrons act as negative charge carriers.

Key Differences Summarized

FeatureIntrinsic SemiconductorExtrinsic Semiconductor
PurityPure formImpurities added (doped)
ConductivityLower conductivityHigher conductivity
Charge CarriersEqual number of electrons and holesUnequal number of electrons and holes
ExamplesPure Silicon, Pure GermaniumN-type Silicon, P-type Germanium
PIN Diode as a Radiation Detector

PIN Diode as a Radiation Detector

Learn how a PIN diode can be used as a radiation detector for monitoring and measurement of ionizing radiation like X-rays and gamma rays.

radiation detection
pin diode
radiation monitoring
Understanding the P-N Junction Diode

Understanding the P-N Junction Diode

Explore the functionality of P-N junction diodes, semiconductor devices with diverse applications in electronics. Learn about their uses in rectification, signal modulation, and more.

diode
pn junction
semiconductor
TVS Diode: Transient Voltage Suppression Explained

TVS Diode: Transient Voltage Suppression Explained

Learn about TVS diodes: how they work, types, applications, and key manufacturers. Protect your circuits from voltage spikes with these semiconductor devices.

diode
transient voltage
voltage suppression