Results and Analysis


Imaging Graphite

Our first images were taken of carbon atoms in a graphite lattice. Filtering these images gives a better representation of atom locations by sharpening the boundaries

Unfiltered Raw ImageFiltered Image

The surface of graphite shows a familiar hexagonal arrangement of atoms.

Our images show this hexagonal arrangement, with a small amount of PZT drift on the part of the STM.

2D view showing hexagonal arrangement3D view showing hexagonal arrangement

Performing a cross-section analysis of the data, we were able to calculate the mean seperation of atoms in the lattice.

We found the mean seperation of atoms to be 2.47 Angstroms, compared with the accepted value of 2.46.


Imaging Molybdenum Disulfide

We also scanned the surface of a MoS2 lattice and obtained the following images.

2D image of MoS23D image of MoS2

Performing a cross section analysis on this data showed that there were smaller bumps between the larger bumps shown in bright green.

Line for cross sectionCross section analysis

We then found the structure for MoS2 and confirmed that the smaller bumps are Molybdenum atoms sandwiched in between two Sulfur atoms.

Drawing a line as indicate by the dotted line above shows the resemblance of our images to this structure.

Line for cross sectionCross section analysis

We measured the seperation of atoms as indicated above and found that we had very different measurements for the mean seperation of atoms than we found in literature. We found the close seperation to be 1.63 Angstroms and the far seperation to be 2.91 Angstroms. These compare with literature values of 3.16 and 5.47 respectively. For both cases, though, our measurements differ from the accepted value by a ratio of around 0.52. For this reason, we feel like the disparities in our data were cause by miscalibration in the STM.

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