Semiconductors Flashcards
In increasing temperature, conductor’s resistivity and conductivity?
Resistivity increases
Conductivity decreases
In increasing temperature, semiconductors resistivity and conductivity?
Resistivity decreases
Conductivity increases
In decreasing temperature, conductor’s resistivity and conductivity?
Resistivity decreases
Conductivity increases
In decreasing temperature, semiconductor’s resistivity and conductivity?
Resistivity increases
Conductivity decreases
Intrinsic semiconductors characteristics
• Pure semiconductors
• Tetravalent crystals 4
• Electric conductivity is low
• Electric conductivity depends on temperature
• Nh = Ne
Extrinsic semiconductors characteristics
• Impure semiconductors
• Trivalent 3 or pentavalent 5
• Electric conductivity is high
• Nh≠Ne
Pentavalent impurity examples
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Arsenic (As) ,phosphorus ( p) ,antimony ( sb)
Trivalent impurity examples
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Boron(B), aluminum (Al), galium(Ga) , indium(In)
N type semiconductors
Are pentavalent
Major electrons
Minor holes
P type semiconductors
Are trivalent
Major holes
Minor electrons
Forward bias meaning
Higher to lower
Reverse bias meaning
Lower to higher (current does not flow)
Current formula for circuit
I = V/R
Resistance in parallel formula
Resistance/no of resistances
Resistance in series formula
They are added
Ni^2 formula
Ne. Nh = Ni^2
When the conductivity of semiconductors is only due to breaking of covalent bonds it is called
Intrinsic semiconductors
1eV in jules
1eV = 1.602×10^-19
What is fermi energy
Highest energy level occupied by electrons in a material at absolute zero temperature (0K)
