LABORATORY EXPERIMENTS GRAPHENE (1+2)

The study of Graphene using Raman spectroscopy and AFM

You will need a Labbook and a USB data key to save your data. Make sure it is exported in a format you can read in Excel.Your objective is to link the thickness of graphene layers (AFM) to spectroscopic information (Raman). Formulate a hypothesis of what you will observe and what links you might observe, based on your literature search.

  1. Literature search - What is Graphene and why is it a technologically important material
  2. Most introductions of papers will specify why people look at graphene and some will also say why study graphene vs CNTs (carbon nanotubes).
  3. The lead research group is that of Geim and Novoselov. They have some of the benchmark papers available
  4. Do a search for graphene in Web of Knowledge to check for some of the most referenced papers on graphene and also get an idea of the increase in publication numbers involving graphene over the last few years.

Limit yourselves to no more than 5-6 papers and maybe one or two of the papers referenced in. Give precedence to the papers containing or detailing Raman spectroscopy and AFM studies of graphene.

  1. Literature search - Get an idea of how graphene is prepared, both using Geim and Novoselov’s technique and what other (CVD for example, Carbon-terminated silicon carbide) techniques there are. Again, no more than 3-5 articles. In this lab, you will be using Geim’s technique (sticky tape).
  1. The first step is to identify potential graphene candidates in an optical microscope. What substrate do you use and why does it have an influence on the colour of graphene under the optical microscope. You will use the optical microscope in the SEM lab. To capture images, you can use either IrfanView or PaintShopPro (TWAIN image capture). NOTE: recognisable features will help you to quickly find the same position in other instruments, such as AFM, Raman, SEM etc. Identify 5-10 candidates to analyse using Raman and the AFM.
  1. RAMAN:
  1. What does Raman spectroscopy measure?
  2. How would spectra from graphite and graphene look like (see all the papers you researched at 1. and 2.)?
  3. Which features of the spectra should tell you if you have one, two or more layers of graphite? What spectral range do you need to record? Note: you will be using the 514 nm laser for the measurements.
  4. Read the SOP (Standard Operating Procedure) for the Renishaw Raman Spectroscope you are going to use. In particular, procedure 5.0.
  5. Do the papers you researched mention any particular/unusal/practical problems relating to measuring Raman spectra from graphene/graphite? Does the power of the laser matter?
  1. AFM:
  2. What will the AFM measure?
  3. What a single sheet of graphene look like measured using the AFM? What will be its’ height/apparent height?
  4. What artefacts may appear in the image (as resulting from the literature you have searched)?
  5. Read the SOP for the Veeco Instruments AFM (attached) that you’re going to use. Find out how you need to scan (speed, magnification) – use images published in the papers for guidance of the size of features you are interested in.

If this is what you choose to write up as an APL (Applied Physics Letters) article, think of how Raman and AFM complement each other and see if you can establish relationships between the observations. The document will be submitted via Turn-it-in.