What is Vacuum Level? - Explained in Detail

  • Thread starter Thread starter shaikss
  • Start date Start date
  • Tags Tags
    Vacuum
Click For Summary

Discussion Overview

The discussion centers around the concept of vacuum level in the context of solid-state physics, particularly its definition and implications in relation to electron behavior and band diagrams under electric fields. Participants seek clarity on the term and its relevance to energy levels in materials.

Discussion Character

  • Conceptual clarification
  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant requests a detailed explanation of vacuum level, citing different definitions encountered online, such as the threshold energy for electrons to leave an atom and the energy of electrons outside a crystal.
  • Another participant expresses unfamiliarity with the term and suggests that the context of its use may be important, recommending further investigation into the original source.
  • A participant notes that the definitions provided by the original poster are essentially similar, discussing the energy required for an electron to escape an atom and the potential energy definitions that can vary based on perspective.
  • One participant defines vacuum level as the energy level where an electron's energy is considered zero, emphasizing that this concept is independent of the electron's physical location.
  • Another participant describes vacuum level in relation to the Fermi level and the work function energy required to remove an electron from a material.

Areas of Agreement / Disagreement

Participants express differing views on the definitions and implications of vacuum level, indicating that multiple competing interpretations exist without a clear consensus.

Contextual Notes

Some definitions and explanations may depend on specific contexts or assumptions that are not fully articulated in the discussion, such as the relationship between vacuum level and other energy levels in materials.

shaikss
Messages
32
Reaction score
0
Hi,

What is vacuum level?
I browsed internet and came across different definitions like
1. Threshold energy with which electron leave the atom.
2. Energy of electron outside the crystal.

Can you please explain in detail what is vacuum level?

At the same time, pls clarify why and how the band diagram diagrams bend when an electric field is applied compared to the band diagram under equilibrium.

Thanks!
 
Engineering news on Phys.org
I haven't heard the term (no surprise there, though).
What was the context in which you read the term? It may be that the author was not being precise and you may need to read his full text to find what he meant. Failing that, email him and demand an explanation!
 
It seems that your definitions are pretty much the same thing. To leave the atom for example in the photoelectric effect it needs a certain minimum energy E. But since energy potentials are only defined up to a number one can either say the electron has potential energy E when free (far away from the atom and not trapped) and when trapped it has energy 0. Or you do it the other way around and say that the free electron has energy 0 and the trapped electron has energy -E which is more common.
 
Vacuum level is the energy level where the energy of an electron becomes zero. It has nothing to do with where the electron is. Electron can be in vacuum level even being inside crystal.

Any standard textbook in VLSI will explain what you need including effect of electric field on band diagram. eg. Streetman and Banerjee.
 
The vacuum level can be described as the energy at the fermi level plus the work function energy needed to remove an electron from the material.
 

Similar threads

  • · Replies 1 ·
Replies
1
Views
3K
Replies
3
Views
2K
  • · Replies 12 ·
Replies
12
Views
3K
  • · Replies 11 ·
Replies
11
Views
5K
  • · Replies 8 ·
Replies
8
Views
3K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 59 ·
2
Replies
59
Views
8K
  • · Replies 15 ·
Replies
15
Views
3K
Replies
3
Views
2K
Replies
1
Views
20K