Difference between Intrinsic and Extrinsic Semiconductor

By Jaxson

Main Difference

Intrinsic semiconductors and extrinsic semiconductors are terms widely used in the study of semiconductors. They both differ largely from each other when we compare their functionality. Intrinsic semiconductor happens to be a genuine semiconductor while their particular conductivity is usually bad and thus, they never find significant application whereas, on the other hand, Extrinsic semiconductor are usually semiconductors whenever a trivalent or even pentavalent impurity is certainly combined with a genuine semiconductor, and  the extrinsic semiconductor is acquired.

Intrinsic Semiconductor

An intrinsic semiconductor, sometimes also known as the pure semiconductor. an intrinsic semiconductor also referred to as an undoped semiconductor or even i-type semiconductor, can be described as genuine semiconductor without any subsequent considerable dopant varieties present. The quantity of charge carriers thus remains based on the particular properties of the material itself as opposed to a number of impurities. In intrinsic semiconductors, the quantity of energized electrons and also a number of holes are usually equal. Holes are represented by p and electrons are represented by n, therefore, n = p in intrinsic semiconductor. The electric powered conductivity associated with intrinsic semiconductors could be as a result of crystallographic flaws or even electron excitation. Within an intrinsic semiconductor, a number of electrons inside conduction band is equivalent to the quantity of holes inside valence band. The conduction band associated with semiconductors like silicon and also germanium is actually empty as well as the valence band is undoubtedly fully loaded with electrons with really low temperature. Germanium as well as silicon possess 4 valence electrons. Each and every atom associated with germanium silicon provides one electron featuring its neighbouring atom. Therefore covalent bond is created. So, there isn’t any totally free electron in germanium and silicon. Because of this, there isn’t any transmission of electricity within them. These kinds of genuine semiconductors are classified as intrinsic semiconductors. In the event that pure semiconductors are usually warmed at a substantial temperature as a result of thermal stress electrons relating to genuine semiconductors will become totally free simply by smashing the bonds. The electrons can easily pass forbidden energy gap in the event the energy of the electrons is large and moved directly into the conduction band. When an electron switches into conduction band coming from valence band generally there an emptiness takes place. The vacancy constitutes a hole and also this gap is equivalent to a positive charge.

Extrinsic Semiconductor

An extrinsic semiconductor is definitely an enhanced intrinsic semiconductor having a tiny amount of impurities additionally added by way of a method, generally known as doping, which usually modifies the particular electrical qualities belonging to the semiconductor and also enhances it’s conductivity. Adding impurities inside the semiconductor materials (doping process) can easily manage their particular conductivity. Doping process generates a couple of groups associated with semiconductors: the negative charge containing conductor known as type conductor and also the positive charge conductor known as the p-type semiconductor. Semiconductors can be found exactly as possibly elements or even compounds. Silicon and also Germanium would be the most typical and frequent used elemental semiconductors. Si in addition to Ge has some sort of crystalline construction referred to as the diamond lattice. That is certainly, every single atom has its own 4 closest neighbours on the edges associated with a typical tetrahedron using the atom by itself staying in the middle. Besides the genuine element semiconductors, numerous alloys along with compounds happen to be semiconductors. The main benefit of the compound semiconductor is because they supply you with the device engineer having a massive amount of energy spaces and also motilities, to ensure that materials can be found along with properties which satisfy specific requirements. A few of these semiconductors are thus called extensive band gap semiconductors

Key Differences

  • In intrinsic semiconductors, an impurity is not added while in extrinsic semiconductors impurity is added.
  • In intrinsic semiconductors, free electrons in the conduction band are equal to the number of holes in the valence band whereas in extrinsic semiconductor free electrons and holes is never equal.
  • Intrinsic semiconductors have low electrical conductivity whereas extrinsic semiconductors have high electrical conductivity.
  • Intrinsic semiconductors conductivity is dependent on temperature but in extrinsic it is dependent from which element it is doped.

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