Why is graphene placed in a cryostat in research?

In summary: Also, is there another situation when it is suitable to cool graphene to cryogenic temperatures?I'm not sure what you're asking.
  • #1
3
0
I have been told when making transport measurements of graphene it is usually placed in a cryostat and cooled to ~ 4K. However I cannot find any sources that back this up and don't fully understand why it is done in the first place.

My thoughts are that it is to measure the carrier mobility with minimal the scattering effects. But is it not more beneficial to measure this at room temperature as this is the most likely situation for graphene based devices.

Also, is there another situation when it is suitable to cool graphene to cryogenic temperatures?
 
Physics news on Phys.org
  • #2
fisher468 said:
I have been told when making transport measurements of graphene it is usually placed in a cryostat and cooled to ~ 4K. However I cannot find any sources that back this up and don't fully understand why it is done in the first place.

My thoughts are that it is to measure the carrier mobility with minimal the scattering effects. But is it not more beneficial to measure this at room temperature as this is the most likely situation for graphene based devices.

Also, is there another situation when it is suitable to cool graphene to cryogenic temperatures?

Unfortunately, without providing any kind of citation to illustrate what you are referring to, it is very difficult to address the specific reason why things are done that way.

Note that if one is trying to study the intrinsic property of the material, one really does not want the properties and the intricate details to be washed out by thermal effects. That is why many studies are done at very low temperatures. Band structure mapping using ARPES, for example, are often done at low temperatures so that the bands can be seen very clearly, especially if they are deeper bands that tend to be broader. If you are also trying to study scattering effects, such as electron-electron scattering, etc, you definiltely want to minimize thermal effects so that you can pick out these weak, subtle phoenomenon.

So without really knowing what specific measurment it is ("transport measurement" doesn't say much), it is impossible to explain why such a thing is done at low temperatures.

Zz.
 
  • #3
ZapperZ said:
"transport measurement" doesn't say much
I think "transport measurement" in this case refers to drain current vs. gate voltage in a FET configuration (transfer curve). It's a pretty standard measurement in graphene research.
fisher468 said:
But is it not more beneficial to measure this at room temperature as this is the most likely situation for graphene based devices.
Sure, you can do these measurements at room temperature. We do this all the time in the lab I work in. The advantage of lower temperatures is that the Dirac point is really well resolved and sharp (because the electrons are less "smeared out" across the Fermi level). This makes it easier to do things like measuring precisely how much various adsorbed species dope the graphene. But you still see a conductivity minimum in the transfer curve of a graphene FET even at room temperature.
 

1. Why is graphene used in cryostat research?

Graphene is a two-dimensional material that is known for its unique properties, such as high electrical and thermal conductivity, mechanical strength, and flexibility. These properties make it an ideal material for studying quantum phenomena, which is one of the main focuses of cryostat research. Additionally, graphene is highly sensitive to changes in temperature and can be used as a sensor for precise measurements of temperature changes in the cryostat.

2. What is a cryostat and how does it work?

A cryostat is a device used to reach and maintain extremely low temperatures, typically below -273°C, the temperature at which all molecular motion stops. It works by using a combination of insulation, cooling mechanisms, and temperature sensors to create a controlled environment with low temperatures. This allows for the study of materials and phenomena at very low temperatures, which is crucial in many areas of research.

3. How is graphene placed in a cryostat for research purposes?

Graphene is typically placed in a cryostat through a process called "transfer printing." This involves depositing a layer of graphene onto a substrate, such as silicon dioxide, and then transferring it onto a target material, such as a superconducting material or a semiconductor. The target material is then placed inside the cryostat for further research and experimentation.

4. What are the advantages of using a cryostat for graphene research?

There are several advantages to using a cryostat for graphene research. Firstly, the extremely low temperatures achieved in a cryostat allow for the study of graphene's unique properties and its behavior in different environments. Secondly, the controlled environment in the cryostat eliminates external factors that could affect the results of the research. Lastly, the use of a cryostat allows for precise temperature control, making it easier to study the effects of temperature on graphene.

5. How does research using graphene in a cryostat benefit society?

The study of graphene in a cryostat has the potential to lead to groundbreaking discoveries and advancements in various fields, such as electronics, energy storage, and quantum computing. These advancements can ultimately benefit society by improving technology, creating new materials and products, and advancing our understanding of fundamental scientific principles. Additionally, the use of graphene in cryostat research can also lead to the development of more efficient and sustainable technologies, contributing to global efforts towards a greener future.

Suggested for: Why is graphene placed in a cryostat in research?

Replies
1
Views
1K
Replies
30
Views
2K
Replies
1
Views
1K
Replies
7
Views
2K
Replies
4
Views
4K
Replies
1
Views
984
Replies
1
Views
2K
Back
Top