How to tell if its a metal or a semiconductor

In summary, according to the Nature paper, a temperature-dependent resistivity measurement on a band semiconductor should show a semiconductor behavior. However, this has not been observed in practice. LEDs require a PN junction, but this does not have anything to do with semiconductors.
  • #1
kini.Amith
83
0
Given a material sample, what are the different experiments that one can perform on it to check if it's a conductor or a semiconductor. For eg, we can measure R at different temperatures. Anything else we can do?
 
Physics news on Phys.org
  • #3
The thread you mentioned only talks about resistivity vs temp. I as wondering if there are other experiments. Is there any difference in how the resistance changes at different AC source frequencies?
 
  • #4
But how complicated do you want the experiment to be?

You can get single-crystal sources and then perform angle-resolved photoemission spectroscopy to see if there are bands crossing the Fermi level. Is this the type of experiments that you want and are able to comprehend?

Zz.
 
  • #5
I don't mind how complicated the experiment becomes practically. I just want to know how we can use our knowledge of conductors and semiconductors to construct experiments that will be at least able to tell the difference in theory. This is a question that is generally asked in Ph.D interviews here in India. Spectroscopy seems like a good option, i'll read more on it.
A friend of mine claims that the AC input frequency vs resistivity curve is different for conductors and Semiconductors, but I can't confirm it from anywhere else. Is this true?
 
  • #7
Semiconductors have 4 electrons in their valence shell.So,what usually is done is gating or perhaps doping to make it either a n-type or a p-type.SO,the material which responds to such techniques would have an increased conductivity.Moreover,why concentrate on the temperature? You do realize that certain semiconductors have excited electrons which relax by emitting light rather than heat(eg- the ones used in LEDs).
 
  • #8
Paradox101 said:
Semiconductors have 4 electrons in their valence shell.So,what usually is done is gating or perhaps doping to make it either a n-type or a p-type.SO,the material which responds to such techniques would have an increased conductivity.Moreover,why concentrate on the temperature? You do realize that certain semiconductors have excited electrons which relax by emitting light rather than heat(eg- the ones used in LEDs).

This is puzzling. The question asked for an experiment that differentiate between a metal and a semiconductor. Why do you go into all that doping stuff?

Secondly, do you know that LEDs require that you form a PN junction? What does that have to do with the topic on hand? Can you cite a temperature-dependent resistivity measurement on a band semiconductor that actually does not show a semiconductor behavior as cited in that Nature paper?

Zz.
 

1. What is the difference between a metal and a semiconductor?

A metal is a material that has a high electrical and thermal conductivity, whereas a semiconductor is a material that has both conductive and insulating properties. Metals have a large number of free electrons that can easily move and conduct electricity, while semiconductors have fewer free electrons and require a certain amount of energy to conduct electricity.

2. How can I determine if a material is a metal or a semiconductor?

The most common way to determine if a material is a metal or a semiconductor is by conducting a simple conductivity test. A metal will have a high conductivity and will allow electricity to flow easily, while a semiconductor will have a lower conductivity and may only allow electricity to flow under certain conditions.

3. What are some physical properties that can help identify a material as a metal or a semiconductor?

Some physical properties that can help identify a material as a metal or a semiconductor include electrical conductivity, melting point, and color. Metals have high electrical conductivity and a high melting point, while semiconductors have lower electrical conductivity and a lower melting point. Metals also tend to have a shiny, metallic appearance, while semiconductors may have a dull or semiconducting color.

4. Can a material be both a metal and a semiconductor?

Yes, some materials can exhibit properties of both a metal and a semiconductor. These materials are known as metalloids, and they have characteristics of both metals and non-metals. Examples of metalloids include silicon, germanium, and arsenic.

5. How do impurities affect the conductivity of a material?

Impurities can greatly affect the conductivity of a material. For example, adding impurities to a semiconductor can create a material with controllable electrical properties, known as a doped semiconductor. This is a common method used in the production of electronic devices such as transistors. On the other hand, impurities in a metal can decrease its conductivity, making it less efficient for conducting electricity.

Similar threads

  • Atomic and Condensed Matter
Replies
0
Views
53
  • Atomic and Condensed Matter
Replies
4
Views
2K
  • Atomic and Condensed Matter
Replies
12
Views
2K
  • Atomic and Condensed Matter
Replies
1
Views
1K
  • Atomic and Condensed Matter
Replies
1
Views
1K
  • Atomic and Condensed Matter
Replies
1
Views
4K
Replies
7
Views
2K
  • Classical Physics
Replies
10
Views
1K
Replies
6
Views
1K
  • Atomic and Condensed Matter
Replies
6
Views
2K
Back
Top