Black phosphorous sample preparation for ultrafast electron diffraction studies
(2020) PHYM01 20201Atomic Physics
Department of Physics
- Abstract
- Since 2004 when mechanical exfoliation was first utilised to produce single layered samples of graphite, 2D materials have gained interest in the scientific community. With the prerequisite that the initial bulk material has a layered structure, these 2D materials have created an opportunity to examine materials on a very small scale as well as opening the possibility of creating smaller electrical components for industrial and commercial use, with well-known and documented parameters. Graphene is known to be strong and is used for batteries, while black phosphorus has potential as a semiconductor, due to the variable band gap, which is dependent on the number of layers of the material, as well as good mobility. In this project, the goal... (More)
- Since 2004 when mechanical exfoliation was first utilised to produce single layered samples of graphite, 2D materials have gained interest in the scientific community. With the prerequisite that the initial bulk material has a layered structure, these 2D materials have created an opportunity to examine materials on a very small scale as well as opening the possibility of creating smaller electrical components for industrial and commercial use, with well-known and documented parameters. Graphene is known to be strong and is used for batteries, while black phosphorus has potential as a semiconductor, due to the variable band gap, which is dependent on the number of layers of the material, as well as good mobility. In this project, the goal is to identify a method for mechanically exfoliating samples of graphite and black phosphorus and suspending these, by transferring the samples to a copper grid. These suspended samples are prepared for the purpose of experiments using ultrafast electron diffraction. This type of experiment is used to understand heating of a material for optronics applications. (Less)
- Popular Abstract
- In 2004, scientists found a way to easily create very thin samples of certain materials, which is called mechanical exfoliation. The first one was thin layers of graphite, and the method was to simply use two pieces of tape to peel down the graphite until only a single layer of atoms remained on the tape. Single layered graphite now has a special name: graphene. Graphene is not the only material that can be peeled down using this method, and all these materials together are now called 2D materials.
2D materials are of interest since they make it possible to create very small electrical components. 2D stands for two dimensional, and means that the material can cover a surface, but is so thin that in some cases the layer only consists of... (More) - In 2004, scientists found a way to easily create very thin samples of certain materials, which is called mechanical exfoliation. The first one was thin layers of graphite, and the method was to simply use two pieces of tape to peel down the graphite until only a single layer of atoms remained on the tape. Single layered graphite now has a special name: graphene. Graphene is not the only material that can be peeled down using this method, and all these materials together are now called 2D materials.
2D materials are of interest since they make it possible to create very small electrical components. 2D stands for two dimensional, and means that the material can cover a surface, but is so thin that in some cases the layer only consists of a single atom. In the industry this is of great use, since smaller components mean that computers e.g. can be made smaller. 2D materials are also being used to create better batteries, which is especially important for the automotive industry when electrical vehicles are becoming more popular. Graphene is the first material in this category, which means that it is also the most well-known and well-studied material. But other materials have similar properties, and different materials are more suitable for different purposes. One new material, which was rediscovered in 2014, is black phosphorus. Black phosphorus is a very interesting material, since it is possible to change the so-called band gap by changing how thick the material is. The band gap means how much energy you have to apply for electricity to run through the material. This is something that cannot be done with graphene, so black phosphorus has the potential to be even better for electrical components than graphene. Another interesting thing about black phosphorus is that 1 % of the human body is composed of phosphorus. Black phosphorus therefore has the potential to be used as a biodegradable material in the human body, for bio-imaging or photodynamic therapy. Potentially, this could be used to locate cancer cells without introducing any new harmful chemicals. The biomarker would then be broken down in the body naturally overtime. But in order for black phosphorus to re-place graphene or be used in biomedical science, more research has to be performed. One way to examine black phosphorus is to first use mechanical exfoliation to create very small flakes, and then placing these flakes on grids. If this is done, it is possible to mount the flake, so that it almost seems like it is suspended freely in the air. This means that no other material is in the way to disturb the measurement. There are different ways to examine a material. One way is to use a laser to shoot at the flake, and for example look at how much weaker the laser is after than before, or how different it is if you change the direction the laser hits the flake. Another way is to use electrons. By using a so called electron gun, a bunch of electrons can be directed to the flake, and then it is possible to look at how they have changed direction after hitting the flake. Since the flakes are very thin, almost every electron can pass through the material, but not every electron can pass without hitting at least one atom. And by finding how much the electrons have been deflected from the initial path, it can actually be calculated how close the atoms are to each other in the flake. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9031449
- author
- Ahrling, Rebecca LU
- supervisor
- organization
- course
- PHYM01 20201
- year
- 2020
- type
- H2 - Master's Degree (Two Years)
- subject
- keywords
- Graphene, Black phosphorus, electron diffraction, 2D material
- language
- English
- id
- 9031449
- date added to LUP
- 2020-11-05 20:56:59
- date last changed
- 2020-11-05 20:56:59
@misc{9031449,
abstract = {{Since 2004 when mechanical exfoliation was first utilised to produce single layered samples of graphite, 2D materials have gained interest in the scientific community. With the prerequisite that the initial bulk material has a layered structure, these 2D materials have created an opportunity to examine materials on a very small scale as well as opening the possibility of creating smaller electrical components for industrial and commercial use, with well-known and documented parameters. Graphene is known to be strong and is used for batteries, while black phosphorus has potential as a semiconductor, due to the variable band gap, which is dependent on the number of layers of the material, as well as good mobility. In this project, the goal is to identify a method for mechanically exfoliating samples of graphite and black phosphorus and suspending these, by transferring the samples to a copper grid. These suspended samples are prepared for the purpose of experiments using ultrafast electron diffraction. This type of experiment is used to understand heating of a material for optronics applications.}},
author = {{Ahrling, Rebecca}},
language = {{eng}},
note = {{Student Paper}},
title = {{Black phosphorous sample preparation for ultrafast electron diffraction studies}},
year = {{2020}},
}