Week+of+9-17-2012

9-17-12 When I came in today, Matt had already been scanning a sample of C-60 on Au(111). Matt said that his first couple scans were pretty good but was unable to get anything of real value after that. He thinks that the sample might be contaminated with Octanethiol from the box. Matt left and I began scanning. My first scan, "AF", had what looked to be like C-60 molecules in large groups but I am not particularly sure. Following it, I took a larger image of the whole region. "AG" was a somewhat interesting image. It wasn't horribly blurry and it had a great deal of features. I zoomed in to a region in the upper right quadrant. I also adjusted the drift and changed the A/D from 4 to 32. This image, "AH", was blurry. There were a lot of streaks and it was difficult to see the molecules. I changed the tip following it. The next image, "AI", resembled that of an Octanethiol sample's surface. This gives some more evidence to our previous conjecture. Matt w ent to tell Prof. Kandel about it. I changed the tip and moved the sample to try to avoid the previous area. After the tip approached, I took a full image, "AJ". This image had drifted a lot since it began. I adjusted it and attempted to scan a 2000 Å region in the right middle portion. The next image, "AK", also drifted near the end. I tried to zoo in to the top half of it with a 1000 Å region. That image, "AL", was very blurry. I could not finish the scan because of the drift. The right half of it looked like it could be mistaken for molecules but the left half looked almost definitely like streaks caused by noise.

9-17-12AF-1000 Å, 16 A/D 200 ms/line The globs of white dots look like what we believe to be the C-60 that we are looking for. The tip with this image is not the best and a heating of this image probably would not have resulted in clear results and would have most likely obscured the surface. 9-17-12AG- 8134.06 Å, 4 A/D, 150 ms/line The hills and valleys are indicative of a gold surface but in this image there is a definite general haze caused by both the tip and the two huge pits in the bottom middle and right middle. No C-60 molecules are visibile at this scale here. Earlier in the summer on July 30, we heated some gold and there was a formation of mounds along the edges of steps like there is in this image. Matt had heated the gold before I came and this was most likely a result of that heating. 9-17-12AH- 2000 Å, 32 A/D, 200 ms/line This image is a fairly blurry one. The streaks indicate noise caused by the tip and poor quality of the sample. There is no clear representation of C-60 in this image and most of it is too fuzzy to discern anything. 9-17-12AI-2000 Å, 4 A/D, 200 ms/line This image, in terms of quality, is much better than the previous one. Although the white dots grouped up on the left side in a horizontal line and around the many triangles are indicative of C-60, the many triangles here suggest the formation of an Octanethiol monolayer. The box that I use for my scanning has fostered research on Octanethiol for several years. Matt and I both believed that the sample could have been easily contaminated by the presence of Octanethiol in the box after being in there for about four hours. We changed the tip after and moved the sample to try to avoid this area. 9-17-12AJ- 8134.06 Å, 4 A/D, 200 ms/line A lot of the blurriness in this image can be somewhat attributed to the quick line time of the scan and the two giant pits in the lower half. Faint white dots are somewhat visible under the haze that covers the whole scan. There are also mounds that hug the edges of steps, another characteristic we have observed in our heating. 9-17-12AK- 2000 Å, 16 A/D, 200 ms/line This image looks fairly interesting. The tiny black pits in this image surrounded by lighter areas could be attributed to Octanethiol molecules or the C-60 molecules because no clear molecules are seen on this surface. 9-17-12-AL- 1000 Å, 16 A/D, 200 ms/line  This image is fairly blurry and no clear C-60 molecules can be seen. The drift would not allow the scan to finish. The streaks indicate a poor tip and a pretty large amount of noise. We changed the tip after to try to get a better scan and were unsuccessful for the rest of the day. 9-18-12 I began by scanning a sample of C-60 on Au(111). I zoomed into an area 1000 Å x 1000 Å in the left middle portion. After AT, I moved the scanning region up and to the left. After AU, I moved it down and slightly to the left. Following AV, I heated the system for 5 seconds. I retracted the tip 15 steps then let it cool for a couple minutes. I approached the tip and it took 17 steps. Afterwards, I let it continue to cool and to drift for a couple more minutes. I adjusted the Z-drift and then scanned a full image, "AW". After "AW", we tried to find the area from before by expanding the XY Scan Range to 3.05 µm. When we tried to scan this area, it was very blurry and had lots of streaks and we assumed that the cause was a ruined tip. This may have also been caused by the settings though. We changed the tip in an attempt to reconcile the situation and were unable to get another image, probably caused by a tip crash.

9-18-12AS-8134.47 Å, 4 A/D, 150 ms/line This picture is an image of the derivative plot to alleviate the problems caused by the large pits in this image. It does, however, make it a bit harder to see any features. I zoomed in to the region in the left middle because it was particularly flat. 9-18-12AT- 1000 Å, 32 A/D, 150 ms/line Much of this image here seems to just be noise but many of the white dots could possibly have been C-60 molecules. 9-18-12AU- 1000 Å, 32 A/D, 150 ms/line Although not very clear in the previous image, it seems clear that the white dots, especially those grouped in the center, are C-60 molecules because of how prevalent they are and how consistent they are. It doesn't seem likely that they are simply noise. 9-18-12AV- 1000 Å, 32 A/D, 150 ms/line This image is somewhat blurry and fuzzy. Streaks are evident through the upper middle portion. We attempted to see the effects on this region from heat but were ultimately unsuccessful.

9-18-12AW- 8134.47 Å, 4 A/D, 150 ms/line This was the after image. This image, like the one from earlier, is also a derivative plot. However, in this image one is able to see more distinct features. One can see the mounds that lie on most of the step edges throughout the image. This has been a fairly common characteristic that we have observed in our heating experiment. We tried to make the XY-scan range bigger to find the region from before and ended up ruining the tip and not being able to scan anything with that tip for the rest of the day.