What is a semi conductor ? desribe any two types of semiconductor?
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heya.
Semiconductors allow to flow a very small quantity of electric current through them at the room temperature. These are the solids with conductivities in the intermediate range from 10–6 to 104 ohm–1m–1.Semiconductors are perfect insulator at absolute zero. Silicon and Germanium are examples of semiconductor.
There are two types of main semiconductors
#n–type semiconductor:
there semiconductors have Electron – rich impurities. Silicon and germanium belong to group 14 of the periodic table and each has four valence electrons . Four out of five electrons are used in the formation of four covalent bonds with the four neighbouring silicon atoms. Extra fifth electron is becomes delocalized. These delocalized electrons increase the conductivity of doped silicon or germanium both . Here the increase in conductivity is due to the negatively charged mobile electron. Hence semiconductors doped with electron–rich impurity are called n–type semiconductor
#p–type semiconductor:–
Si or Ge can also be doped with a group 13 element. The elements of group 13 contains only three valence electrons. Elements of 14th group have has 4 valence electron. The place where the fourth valence electron is missing is called electron hole .An electron from a neighbouring atom can come and fill the electron hole, but in doing so it would leave an electron hole at its original position. If it happens, it would appear as if the electron hole has moved in the direction opposite to that of the electron that filled it. Under the influence of electric field, electrons would move towards the positively charged plate through electronic holes, but it would appear as if electron holes are positively charged and are moving towards negatively charged plate. This type of semi conductors are called p–type semiconductors.
tysm......@kundan
Semiconductors allow to flow a very small quantity of electric current through them at the room temperature. These are the solids with conductivities in the intermediate range from 10–6 to 104 ohm–1m–1.Semiconductors are perfect insulator at absolute zero. Silicon and Germanium are examples of semiconductor.
There are two types of main semiconductors
#n–type semiconductor:
there semiconductors have Electron – rich impurities. Silicon and germanium belong to group 14 of the periodic table and each has four valence electrons . Four out of five electrons are used in the formation of four covalent bonds with the four neighbouring silicon atoms. Extra fifth electron is becomes delocalized. These delocalized electrons increase the conductivity of doped silicon or germanium both . Here the increase in conductivity is due to the negatively charged mobile electron. Hence semiconductors doped with electron–rich impurity are called n–type semiconductor
#p–type semiconductor:–
Si or Ge can also be doped with a group 13 element. The elements of group 13 contains only three valence electrons. Elements of 14th group have has 4 valence electron. The place where the fourth valence electron is missing is called electron hole .An electron from a neighbouring atom can come and fill the electron hole, but in doing so it would leave an electron hole at its original position. If it happens, it would appear as if the electron hole has moved in the direction opposite to that of the electron that filled it. Under the influence of electric field, electrons would move towards the positively charged plate through electronic holes, but it would appear as if electron holes are positively charged and are moving towards negatively charged plate. This type of semi conductors are called p–type semiconductors.
tysm......@kundan
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Hey !!
SEMICONDUCTOR :- A material whose electrical conductivity is of the order of 10⁻⁶ - 10⁴ ohm⁻¹ cm⁻¹ is called a semiconductor. It allows flow of current only in one direction.
There are 2 types of semiconductors
1) n-type semiconductor
2) p-type semiconductor
n-type semiconductor :- These semiconductor conduct electricity due to presence of free electrons.
p-type semiconductor :- Group - 13 like B , Al , Ga doped crystals of Si are called p-type semiconductor. Since holes (positive in charge) appear to be responsible for the semiconducting properties.
Good luck !!
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