How ionized radicals bind to Ir(111) supported graphene
(2018) FYSK02 20171Department of Physics
Synchrotron Radiation Research
- Abstract
- In this thesis radical adsorption onto Ir(111) supported graphene at room temperature is studied using scanning tunneling microscopy. The radicals were formed in by thermal cleavage of C2H4 molecules. First of all, the analysis of the location of the adsorbed radicals reveals that the radicals prefer to adsorb in so-called HCP/FCC areas of the graphene film where the graphene film is located closer to the Ir(111) substrate. Further, the carbon bond configuration in these areas allows rehybridization from graphite like bonding to diamond like bonding upon radical adsorption. Secondly, the analysis of the relative distance between adsorbed radicals demonstrates that radicals have a tendency to bind in the immediate proximity of other... (More)
- In this thesis radical adsorption onto Ir(111) supported graphene at room temperature is studied using scanning tunneling microscopy. The radicals were formed in by thermal cleavage of C2H4 molecules. First of all, the analysis of the location of the adsorbed radicals reveals that the radicals prefer to adsorb in so-called HCP/FCC areas of the graphene film where the graphene film is located closer to the Ir(111) substrate. Further, the carbon bond configuration in these areas allows rehybridization from graphite like bonding to diamond like bonding upon radical adsorption. Secondly, the analysis of the relative distance between adsorbed radicals demonstrates that radicals have a tendency to bind in the immediate proximity of other radicals. (Less)
- Popular Abstract
- In today’s industrialized world, the need for better and more efficient materials is increasing at an incredible rate. The Earth’s limited resources will not able to keep up with the growing demand unless scientists find new materials and innovative ways to use them more efficiently. One-way scientists learn about a materials property is to use instruments which allow them to study the interaction that occurs between two different materials surfaces on the atomic scale. In this project, the interaction occurring on the relatively new material graphene was studied.
Graphene, known by many as the ‘miracle’ material, has been around for a long time, but the technique to create it was not found until 2004. Graphene is comprised of a single... (More) - In today’s industrialized world, the need for better and more efficient materials is increasing at an incredible rate. The Earth’s limited resources will not able to keep up with the growing demand unless scientists find new materials and innovative ways to use them more efficiently. One-way scientists learn about a materials property is to use instruments which allow them to study the interaction that occurs between two different materials surfaces on the atomic scale. In this project, the interaction occurring on the relatively new material graphene was studied.
Graphene, known by many as the ‘miracle’ material, has been around for a long time, but the technique to create it was not found until 2004. Graphene is comprised of a single layer of carbon atoms which gives it incredible strength and an outstanding ability to conduct electricity and heat. The combination of these properties has led to the intense study of graphene for the last thirteen years. One idea that has gained a lot of traction is the possibility to attach small structures on graphene in order manipulate and take advantage of its properties. The process of attaching and the studying of where the said structures attached was the area of focus for this project.
In this project, the first step was to grow pure graphene in an environment where it could be isolated and studied in detail. To do this, an ultra-high-vacuum (UHV) container was prepared. To be classified as UHV the pressure inside of the chamber must be 10-9 mbar or lower which is 1012 times lower than the pressure at sea level (that is 1,000,000,000,000 times smaller). This environment was created using several different vacuum pumps. In the UVH, pure graphene was then grown. The graphene was then exposed to radicals of the organic compound Ethelyn, C2H4, which were generated using a cracker. A cracker is essentially a material that is heated and upon interaction with the organic compounds, breaks the compound into smaller pieces, i.e. the radicals, which can then bind to the graphene surface.
A picture of the resulting graphene with the radicals on top of it was taken using scanning tunneling microscopy (STM). An STM is in its essence an advanced camera that takes advantage of quantum tunneling effects to generate pictures with atomic resolution. One of the images taken can be seen in figure 1. This image shows the radicals as the bright outlined dark protrusions on top of a large scale hexagonal pattern which is the graphene. Upon a closer inspection, it was found that these radicals tended to place themselves in certain domains on the graphene and that they have a propensity to
be in the immediate vicinity of another radical as can be seen in the upper portion of the image.
The collection of this data could serve as a starting point if one wants to extend on these results. Identifying the nature of the radicals would be first step in refining the experiment. After this there are several avenues one could go down and research, including the potential application of the radical bonded graphene for use in electronics or as a catalytic support. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/8934165
- author
- Johansson, David LU
- supervisor
-
- Jan Knudsen LU
- Foteini Ravani LU
- organization
- course
- FYSK02 20171
- year
- 2018
- type
- M2 - Bachelor Degree
- subject
- keywords
- Graphene, Radicals
- language
- English
- id
- 8934165
- date added to LUP
- 2018-01-30 11:24:38
- date last changed
- 2018-01-30 11:24:38
@misc{8934165,
abstract = {{In this thesis radical adsorption onto Ir(111) supported graphene at room temperature is studied using scanning tunneling microscopy. The radicals were formed in by thermal cleavage of C2H4 molecules. First of all, the analysis of the location of the adsorbed radicals reveals that the radicals prefer to adsorb in so-called HCP/FCC areas of the graphene film where the graphene film is located closer to the Ir(111) substrate. Further, the carbon bond configuration in these areas allows rehybridization from graphite like bonding to diamond like bonding upon radical adsorption. Secondly, the analysis of the relative distance between adsorbed radicals demonstrates that radicals have a tendency to bind in the immediate proximity of other radicals.}},
author = {{Johansson, David}},
language = {{eng}},
note = {{Student Paper}},
title = {{How ionized radicals bind to Ir(111) supported graphene}},
year = {{2018}},
}