Podcast
Questions and Answers
They are called acceptor atoms because they introduce the absence of electrons in covalent bonds in the extrinsic material. With the addition of a trivalent material, the covalent bonds are still present but there is now an absence of electrons in some of the covalent bonds due to the ______ atom.
They are called acceptor atoms because they introduce the absence of electrons in covalent bonds in the extrinsic material. With the addition of a trivalent material, the covalent bonds are still present but there is now an absence of electrons in some of the covalent bonds due to the ______ atom.
impurity
The resulting vacancy of electron in the covalent bond is called ______ (represented by a plus (+) sign, but not necessarily having a positive charge).
The resulting vacancy of electron in the covalent bond is called ______ (represented by a plus (+) sign, but not necessarily having a positive charge).
hole
The transfer of holes (or transfer of electrons from one hole to another) constitutes a ______ flow.
The transfer of holes (or transfer of electrons from one hole to another) constitutes a ______ flow.
current
Due to vacancy of electrons in covalent bonds in a p-type material, the majority carriers in a p-type material are ______.
Due to vacancy of electrons in covalent bonds in a p-type material, the majority carriers in a p-type material are ______.
Signup and view all the answers
Due to impurities, p-type materials also have ______ carriers which are electrons.
Due to impurities, p-type materials also have ______ carriers which are electrons.
Signup and view all the answers
If a valence electron acquires sufficient kinetic energy to break its covalent bond and to fill the void created by a hole, then a hole will be created in the covalent bond that released the electron, and a transfer of hole happens. This process leads to ______ creation.
If a valence electron acquires sufficient kinetic energy to break its covalent bond and to fill the void created by a hole, then a hole will be created in the covalent bond that released the electron, and a transfer of hole happens. This process leads to ______ creation.
Signup and view all the answers
For the n - type material, the concentration of electrons (majority carrier) is 1x 10^15 electrons/cm3, while the concentration of holes (minority carrier) is 225,000 __________ /cm3
For the n - type material, the concentration of electrons (majority carrier) is 1x 10^15 electrons/cm3, while the concentration of holes (minority carrier) is 225,000 __________ /cm3
Signup and view all the answers
In an extrinsic semiconductor, the doping process determines the concentration of free electrons and __________.
In an extrinsic semiconductor, the doping process determines the concentration of free electrons and __________.
Signup and view all the answers
Generally, the more acceptor impurity atoms (trivalent) are added, the more __________ are created.
Generally, the more acceptor impurity atoms (trivalent) are added, the more __________ are created.
Signup and view all the answers
The more donor impurity atoms (pentavalent) are added, the more free __________ are created.
The more donor impurity atoms (pentavalent) are added, the more free __________ are created.
Signup and view all the answers
The Law of Electrical Neutrality states that in a material, the sum of ______ charges equals the sum of positive charges.
The Law of Electrical Neutrality states that in a material, the sum of ______ charges equals the sum of positive charges.
Signup and view all the answers
Once donor and/or acceptor atoms are added to an intrinsic semiconductor, ions are created due to the addition of electrons to acceptor atoms and the loss of electrons from donor atoms. Acceptor atoms which have gained electrons are now negatively charged, and donor atoms which have lost electrons are now positively charged. This is called the Law of Electrical __________.
Once donor and/or acceptor atoms are added to an intrinsic semiconductor, ions are created due to the addition of electrons to acceptor atoms and the loss of electrons from donor atoms. Acceptor atoms which have gained electrons are now negatively charged, and donor atoms which have lost electrons are now positively charged. This is called the Law of Electrical __________.
Signup and view all the answers
In an intrinsic semiconductor, the Law of Electrical Neutrality equation simplifies to: ______ = ______.
In an intrinsic semiconductor, the Law of Electrical Neutrality equation simplifies to: ______ = ______.
Signup and view all the answers
Although ions are present in the extrinsic semiconductor material, the entire material is still electrically neutral because the number of positive ions is equal to the number of negative ions. This is a manifestation of the Law of Electrical __________.
Although ions are present in the extrinsic semiconductor material, the entire material is still electrically neutral because the number of positive ions is equal to the number of negative ions. This is a manifestation of the Law of Electrical __________.
Signup and view all the answers
In n-type semiconductors, the number of ______ atoms is zero.
In n-type semiconductors, the number of ______ atoms is zero.
Signup and view all the answers
The Law of Electrical Neutrality applies to p-type semiconductors where the number of ______ atoms is zero.
The Law of Electrical Neutrality applies to p-type semiconductors where the number of ______ atoms is zero.
Signup and view all the answers
A germanium material doped with 1015 donor atoms/cm3 and 2 x 1014 acceptor atoms/cm3 exemplifies the concept of ______ impurity atoms.
A germanium material doped with 1015 donor atoms/cm3 and 2 x 1014 acceptor atoms/cm3 exemplifies the concept of ______ impurity atoms.
Signup and view all the answers
In semiconductors, the creation of holes results in the generation of ______ carriers.
In semiconductors, the creation of holes results in the generation of ______ carriers.
Signup and view all the answers
Study Notes
Extrinsic Semiconductor Material
- Acceptor atoms introduce the absence of electrons in covalent bonds, resulting in a vacancy of electrons, known as a hole.
- The absence of electrons in the covalent bond is represented by a plus (+) sign, but not necessarily having a positive charge.
- Holes readily accept electrons, and when a valence electron acquires sufficient kinetic energy to break its covalent bond and fill the void created by a hole, a hole is created in the covalent bond that released the electron, and a transfer of hole happens.
- The transfer of holes (or transfer of electrons from one hole to another) constitutes a current flow.
P-Type Extrinsic Semiconductor Material
- The majority carriers in a p-type material are holes.
- Minority carriers in a p-type material are electrons.
- The number of holes in a p-type material far outweighs the number of free electrons.
N-Type Extrinsic Semiconductor Material
- The majority carriers in an n-type material are free electrons.
- Minority carriers in an n-type material are holes.
- The concentration of electrons (majority carrier) in n-type silicon is approximately 1x 10^15 electrons/cm3.
Law of Electrical Neutrality
- The law states that the total positive charge concentration is equal to the total negative charge concentration in an extrinsic semiconductor material.
- The equation for Law of Electrical Neutrality is: n + NA = p + ND
- Where: ND = concentration of donor impurity, NA = concentration of acceptor impurity, n = concentration of free electrons, and p = concentration of holes.
Application of Law of Electrical Neutrality
- For intrinsic semiconductors, the equation for Law of Electrical Neutrality reduces to: n = p
- For n-type semiconductors, the equation for Law of Electrical Neutrality reduces to: n = p + ND
- For p-type semiconductors, the equation for Law of Electrical Neutrality reduces to: n + NA = p
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Explore the concept of acceptor atoms introducing absence of electrons in covalent bonds and creating holes in semiconductor materials. Understand how trivalent impurity atoms impact the electron structure in semiconductors.
