Physics for Electrical Engineering: Unit V: Nano Devices

Significance between fermi energy and volume of the material

Nano Devices

It is defined as the highest energy level occupied by the electron at OK in metal.

SIGNIFICANCE BETWEEN FERMI ENERGY AND VOLUME OF THE MATERIAL

Fermi Energy

It is defined as the highest energy level occupied by the electron at OK in metal.

In terms of distribution of energy, solids have wide energy bands whereas atoms have thin, discrete energy states.

Now rearranging eqn (4) for the Fermi energy of a conductor, we have


Here, n is the only variable and all the other terms are constants. Thus, Fermi energy of the conductor just depends on the number of free electrons per unit volume ie., electron density ne


As the electron density is a property of the material, Fermi energy does not vary with the material's size. EF is the same for a particle of a solid as it is for a solid itself.

This is the case applicable for conductors, insulators and semiconductors. The average spacing between energy states is inversely proportional to the volume of the solid

ΔE ∝ 1 / ɑ3  ...(7)

 

Physics for Electrical Engineering: Unit V: Nano Devices : Tag: : Nano Devices - Significance between fermi energy and volume of the material