Today we will see about Bonding in semiconductors or Bond model of semiconductor .A semiconductor atom that has four valence electrons and four holes requires four more electrons to completely fill the outermost orbit (the total number must be eight). Atoms in a crystal they are arranged so closely that the electrons orbit in valence layers of two atoms. Each valence shell electron fills the hole of the neighboring atom as shown in the given figure.
A semiconductor have how many valance electron ?
A semiconductor has need of four valence electron ans also require four holes to complete outer most orbit.
Bonding in semiconductors or Bond model
In the given figure, the atoms of the silicon material is shown. For simple understanding, only the outermost orbitals of atoms are shown. The exchange of electrons from neighboring atoms to satisfy the requirement of eight electrons in the valence shell on one atom is called a covalent bond.Due to the covalent bond, that is, the bond through the exchange of electrons, it is observed that the valence layers of all the electrons are full, that is, they all have eight electrons in their outermost orbit.
At absolute zero temperature there will be no free electrons in the crystal.
However, although electrons are attached to their atoms due to the covalent bond, an increase in temperature breaks part of the covalent bond and releases some electrons.
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| Bonding in semiconductors |
Intrinsic or Pure Semiconductors
A semiconductor material, silicon or germanium where the electrons are attached to their respective atoms and are not free to conduct electric current, are called intrinsic or pure semiconductors. When the temperature of the crystal rises, external energy in the form of heat is applied to the semiconductor material.
What is a hole in semiconductor ? Bonding in semiconductors
This thermal energy allows the valence electrons to acquire enough energy to separate from the atoms and become free electrons. "When an electron comes out to free itself, it leaves an empty space called a hole."
What is electron-hole pair in semi conductor ?
We are discussing the topic of Bonding in semiconductors or Bond model of semiconductor .
An electron-hole pair
"For every free electron there will be a corresponding hole produced, which is called an electron-hole pair."
what happen when temperature of semi-conductor is increase ?
A large number of electron-hole pairs of are formed due to the increase in the temperature of the semiconductor.
Recombination in semiconductor
When the electrons are released, they are attracted to and fall into a hole created by another electron. This fusion of electrons and free holes is called recombination.The time of creation of a free electron and its fall in a hole is very fast and the necessary time is of the order of nanoseconds. Therefore, pure silicon or germanium is not of much use in electronics, except for manufacturing heat or light sensitive resistors.
What is extrinsic semiconductor ?
The process of adding a quintessential element or a pure element to a semiconductor element is called doping. Doped semiconductor is called extrinsic semiconductor. The doping material that is added to a pure semiconductor is also known as an impurity material. Extrinsic semiconductors are named n-type semiconductors or p-type semiconductors, respectively, depending on whether a pentavalent or trivalent doping material is added.
Doping in semi conductor
Conductivity of semiconductor materials can be increased by adding some amount of other material which have three or five valence electrons.So the process of adding these material is called doping and the final material which is formed by doping is called extrinsic semiconductors.
Conclusion
I hope this information about Bonding in semiconductors or Bond model of semiconductor will help you to provide correct information by me and our team ,this will definitely help you to enhance your knowledge about bonding in semiconductor .
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