Number of electrons per unit volume

Click For Summary
SUMMARY

The number of conduction electrons per unit volume, denoted as n, remains constant in conductors regardless of temperature, while in semiconductors, this number varies with temperature due to thermal excitation. In semiconductors, electrons can be promoted to the conduction band when thermal energy increases, allowing for greater conductivity. Conversely, conductors have a saturation level of free electrons, meaning that additional heating does not increase their number. The distinction between free electrons and bound electrons is crucial; free electrons participate in conduction, while bound electrons are tightly held within atomic structures.

PREREQUISITES
  • Understanding of conduction and valence bands in solid-state physics
  • Knowledge of thermal energy effects on electron behavior
  • Familiarity with the concept of free electrons versus bound electrons
  • Basic principles of electrical conductivity in materials
NEXT STEPS
  • Research the role of thermal excitation in semiconductor conductivity
  • Explore the differences between conductors and semiconductors in detail
  • Learn about the band theory of solids and its implications for electron behavior
  • Investigate the effects of temperature on electrical properties of various materials
USEFUL FOR

Students and professionals in physics, electrical engineering, and materials science who are studying the behavior of electrons in conductors and semiconductors.

thereddevils
Messages
436
Reaction score
0
Why is the number of electrons per unit volume , n fixed in a conductor regardless of the temperature while its not in semiconductors ??
 
Physics news on Phys.org
I think you mean number of free/conduction electrons.
In a semiconductor, electrons can promoted to the conduction band by thermal energy; i.e. by raising the temperature of the material. In a conductor, the number of free/conduction electrons is more or less at saturation, and heating the material does not produce any more.

Of course the total number of electrons in the material is not affected by temperature.
 
Stonebridge said:
I think you mean number of free/conduction electrons.
In a semiconductor, electrons can promoted to the conduction band by thermal energy; i.e. by raising the temperature of the material. In a conductor, the number of free/conduction electrons is more or less at saturation, and heating the material does not produce any more.

Of course the total number of electrons in the material is not affected by temperature.

thanks so free electrons and electrons are different ? I thought they are the same .
 
They are only "different" in that in any material some are free to take part in conduction and others are not.
Some are situated deep in the lower energy levels of the atom where they are strongly bound, while others are in the outer levels where they are weakly bound.
 

Similar threads

What will be the number of collision per second in a unit area?
  • · Replies 12 ·
Replies
12
Views
2K
Three Phase Per Unit System - Mark up, represent as single phase equiv
  • · Replies 0 ·
Replies
0
Views
1K
Undergrad Number of Higgs "particles" per unit volume
  • · Replies 4 ·
Replies
4
Views
1K
Free energy per unit volume of an ideal gas
  • · Replies 3 ·
Replies
3
Views
3K
Electron moving to the face of plate from depth d
  • · Replies 4 ·
Replies
4
Views
1K
Finding the excess electrons per lead atom
  • · Replies 2 ·
Replies
2
Views
3K
Finding the magnitude of the hydrostatic force per unit of circumference
  • · Replies 5 ·
Replies
5
Views
2K
Fraction of valence electrons free for conduction
  • · Replies 8 ·
Replies
8
Views
2K
Photons per Unit Volume (Quantum)
  • · Replies 4 ·
Replies
4
Views
4K
How Many Electrons Does a Cathode Ray Tube Emit Per Second?
  • · Replies 9 ·
Replies
9
Views
3K