When a pure semiconductor is heated, its resistance:
As temperature increases electrons from the valence band go to the conduction band, so conductivity increases hence resistance decreases.
What is the order of forbidden gap in the energy bands of silicon?
Silicon has a forbidden gap of 1.1 eV at 300 K temperature.
The densities of electrons and holes in an extrinsic semiconductor are 8 x 1015 cm-3 and 5 x 1012 cm-3 respectively. The mobilities of electrons and holes are respectively 23 x 103 cm3 / Vs and 102 cm3 / Vs. Which type of semiconductor is it?
It is an N-type semiconductor because the density of electrons is more here.
A semiconductor is formed by:
Arrange the materials in ascending order of energy band gaps:
In a semiconductor, current conduction is due to:
There are two types of semiconductors: p-type and n-type. Therefore both holes and electrons conduct current respectively.
Electrons moving like molecules of gas exist in:
Electrons in metal behave as gas.
What is the value of the dielectric constant of air?
The dielectric constant of a medium K = ∈/∈0
where ∈ is the permittivity of the medium.
For air, ∈ = ∈0
⟹ K = 1
Mobilities of electrons and holes in a sample of intrinsic germanium semiconductor at room temperature are 0.36m2/volt-sec and 0.17 m2/volt-sec respectively. If the electron and hole densities are each equal to 2.5 X 1019/m3, the conductivity is ______.
Here n = 2.5 * 1019 / m3 ; e = 1.6 * 10-19 C, µh = 0.17 m2/Volt-sec
σ = ne(µe + µh)
σ = (2.5 * 1019) * (1.6 * 10-19) (0.36 + 0.17) = 2.12 S/m
In a semiconductor, the forbidden energy gap between the valence band and conduction band is about:
In semiconductors, the forbidden gap between the valence band and conduction band is very small. It has a forbidden gap of about 1 electron volt (eV).