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Angular dependence of the Raman active phonon modes of Black Phosphorus

Dominguez, Armand LU (2019) FYSM60 20191
Atomic Physics
Department of Physics
Abstract
This Master’s project presents on the angular dependence of the intensity of the Raman active phonon modes of Black Phosphorus (BP), a layered 2D material with unique and attractive characteristics to the scientific and engineering community. Raman spectroscopy is an indispensable tool in quick and unobtrusive analysis of chemical structures.
In this Master project, the structure of BP is analyzed through polarized Raman excitation. The incident polarization is varied to investigate the effect on the various detectable Raman active modes in BP. A Raman microscope with a 532 nm laser was used to excite BP flakes mechanically exfoliated from a source. The amplitude of the peaks in the Raman spectra are plotted against the angle that they... (More)
This Master’s project presents on the angular dependence of the intensity of the Raman active phonon modes of Black Phosphorus (BP), a layered 2D material with unique and attractive characteristics to the scientific and engineering community. Raman spectroscopy is an indispensable tool in quick and unobtrusive analysis of chemical structures.
In this Master project, the structure of BP is analyzed through polarized Raman excitation. The incident polarization is varied to investigate the effect on the various detectable Raman active modes in BP. A Raman microscope with a 532 nm laser was used to excite BP flakes mechanically exfoliated from a source. The amplitude of the peaks in the Raman spectra are plotted against the angle that they were measured in. The classical model for the Raman tensor was used but it was inadequate in it’s ability to predict data in the cross polarized configuration. An improved model taking the linear dichroism and
the degradation effects of BP into account substantially improved the fit.
All in all, with the strange characteristics of BP factored, phonon mode control through polarized Raman excitaion much of the modes followed the complex angular dependence set by theory but not all of the data points were accounted for by the complex dependence and degradation. (Less)
Popular Abstract
Once in a while, a new material emerges with unique characteristics that make it of particular interest to many. Black Phosphorus (BP) may be one of those peculiar materials.
BP is made of many sheets; like stacks of paper. It is possible to keep peeling off the sheets of BP until one only has a single sheet left. Doing so reveals BP’s interesting properties.
When it becomes several sheets thin it acts like a semiconductor; one of the necessary parts of a computer chip. If the semiconductor part of a computer chip is small then the overall size of the computer chip can be even smaller, and if the computer chip is smaller then the same device can be made more compact or more powerful for the same size.
A problem when working with these... (More)
Once in a while, a new material emerges with unique characteristics that make it of particular interest to many. Black Phosphorus (BP) may be one of those peculiar materials.
BP is made of many sheets; like stacks of paper. It is possible to keep peeling off the sheets of BP until one only has a single sheet left. Doing so reveals BP’s interesting properties.
When it becomes several sheets thin it acts like a semiconductor; one of the necessary parts of a computer chip. If the semiconductor part of a computer chip is small then the overall size of the computer chip can be even smaller, and if the computer chip is smaller then the same device can be made more compact or more powerful for the same size.
A problem when working with these thin materials is that it is difficult to determine the orientation of the material which can be important in some applications. Many methods can determine the orientation of the material but can damage the item when done. However, there exists a method called Raman spectroscopy which uses the fact that sometimes light does not bounce back the same way when it hits an object. Sometimes the light that bounces off the object is a different color. The amount of light that is a different color depends on the object that one is shining light on. In the case of BP, this also depends on the angle you shine the light on. Because of this, one can map the orientation of BP using Raman spectroscopy, the technique used in this project. (Less)
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author
Dominguez, Armand LU
supervisor
organization
course
FYSM60 20191
year
type
H1 - Master's Degree (One Year)
subject
keywords
Black Phosphorus, Raman Spectroscopy
language
English
id
8996209
date added to LUP
2019-10-07 11:50:51
date last changed
2020-01-01 03:38:56
@misc{8996209,
  abstract     = {This Master’s project presents on the angular dependence of the intensity of the Raman active phonon modes of Black Phosphorus (BP), a layered 2D material with unique and attractive characteristics to the scientific and engineering community. Raman spectroscopy is an indispensable tool in quick and unobtrusive analysis of chemical structures.
In this Master project, the structure of BP is analyzed through polarized Raman excitation. The incident polarization is varied to investigate the effect on the various detectable Raman active modes in BP. A Raman microscope with a 532 nm laser was used to excite BP flakes mechanically exfoliated from a source. The amplitude of the peaks in the Raman spectra are plotted against the angle that they were measured in. The classical model for the Raman tensor was used but it was inadequate in it’s ability to predict data in the cross polarized configuration. An improved model taking the linear dichroism and
the degradation effects of BP into account substantially improved the fit.
All in all, with the strange characteristics of BP factored, phonon mode control through polarized Raman excitaion much of the modes followed the complex angular dependence set by theory but not all of the data points were accounted for by the complex dependence and degradation.},
  author       = {Dominguez, Armand},
  keyword      = {Black Phosphorus,Raman Spectroscopy},
  language     = {eng},
  note         = {Student Paper},
  title        = {Angular dependence of the Raman active phonon modes of Black Phosphorus},
  year         = {2019},
}