Week+of+3-11-2013

3-13-2013 I came in today and began scanning a sample of Octanethiol on Au(111). I was scanning at a temperature of -6.8 degrees Celsius AP-8000 Å, 32 A/D, 100 ms/line AQ-8000 Å, 32 A/D, 100 ms/line-zoomed into upper left AR-2000 Å, 64 A/D, 100 ms/line-Following this image, I moved the scanning region to the right. In this and the following image, we can see some sort of structures that slightly resemble that of Octanethiol molecules. AT-2000 Å, 64 A/D, 50 ms/line AU-500 Å, 128 A/D, 25 ms/line. I utilized the range function after this image. I moved the entire macro scanning range to the left a bit. This image is incredibly blurry which can be possibly attributed to the combination of the high A/D gain and the incredibly low line time which could have possibly caused the smudged like surface seen here. AV-8000 Å, 32 A/D, 100 ms/line- This is a slightly better image than the previous one. I zoomed in to the upper middle. AW-2000 Å, 64 A/D, 100 ms/line. Based on the quality of the previous image, I find this one to be a bit disappointing. I think that this is probably due to the extended line time used in the scanning of this image. I reduced it and scanned the same region. AX-2000 Å, 64 A/D, 50 ms/line. This image gives a much clearer picture of the gold surface than the previous one. The packing of the Octanethiol molecules is most evident in the top third of the image while the rest of the image is sort of blurred out by the very nature of the surface being uneven. I zoomed in to the upper middle of this image. AY-500 Å, 128 A/D, 25 ms/line- Here we have a much smaller image which seems to display a surface coated with Octanethiol molecules but in a way that is incredibly blurry and inadequate for actual data analysis. This is probably caused by the tip or by the surface affecting the tip. I moved the image up and to the left. AZ-500 Å, 128 A/D, 25 ms/line- This image is a tad bit blurrier than the previous one. The streaks that mar the center of the page are indicative of a problem with either the tip or the surface causing problems with the tip. BA-500 Å, 128 A/D, 25 ms/line. This image showed a similar lack of quality as the previous one. I zoomed back out and moved to the lower middle of AV. BC-2000 Å, 32 A/D, 100 ms/line- I zoomed in to the bottom right of this image, which is fairly blurry yet still exhibits a small resemblance to an Octanethiol surface. BD-1000 Å, 64 A/D, 37.5 ms/line- I moved to the middle of the left side to avoid the giant pit in the middle in this image, which probably magnified the blurriness seen here. BE-1000 Å, 64 A/D, 37.5 ms/line- I zoomed in to try to get a better look at the surface seen here. BF-500 Å, 128 A/D, 25 ms/line. This is sort of what I had expected from this small of an area based on what I had been getting previously. I turned the gain down afterwards and scanned the same region. BG-500 Å, 128 A/D, 25 ms/line. This image here contains a great deal less noise than all of the previous ones and it seems as if I should have noticed that the gain was the problem far earlier but I will definitely know the first place to look next time something similar happens. BH-500 Å, 128 A/D, 25 ms/line. Here is a scan of the same region before in the Y-direction. Unfortunately it does not look very similar at all. BI-1500 Å, 64 A/D, 50 ms/line. BJ-1500 Å 64 A/D, 50 ms/line. This is a scan in the y-direction of the region seen in BI, which once more looks almost nothing like the scan in the x-direction. BK-500 Å, 128 A/D, 10 ms/line. Here is an actually semi-decent image of the Octanethiol molecules on the surface. However, they are also fairly stretched in the X-direction which poses a concerning problem about the scope's ability. BL-500 Å, 128 A/D, 10 ms/line. This should be a scan in the Y-direction of BK but resembles BK in almost no way at all. BM-500 Å, 128 A/D, 10 ms/line. This is an image of incredibly poor quality. There are a high amount of streaks and little, if anything, can actually be seen on the surface. I scanned another large area after this. BN-8000 Å, 32 A/D, 200 ms/line. The features in this image seem to be sort of stretched in the direction and give it a very fuzzy sort of look. BO-8000 Å, 32 A/D, 100 ms/line- I took a scan of BN in the Y-direction to test whether or not it would actually scan the same thing and for the first time all day it actually worked.

3-14-2013 Today, Prof. Kandel was in the lab and, after seeing the stretched nature of the images from yesterday, he suggested, based on prior experience, that what was causing the scans to be stretched was a blown High voltage plate in the electronics used for the scope. Matt tested out the X and Y voltage plates and found that the X plate was indeed no longer functioning properly. Matt and I went to search for another one around the lab and found one. We replaced it, re-calibrated the scope, and began scanning a sample of Octanethiol on Au(111).

This day was easily the most successful and fruitful day of scanning that I have ever had in the lab. AZ-1000 Å, 64 A/D, 50 ms/line. Here we have a surface with one of the best representations of a monolayer on a Gold surface that Matt and I had ever seen. The molecules are arranged in a hexagonal packing manner on the surface which is precisely the way in which Octanethiol molecules are supposed to arrange themselves on the surface. This is most evident in the upper right and lower left quadrants. I zoomed out slightly to take a larger image.

BA-2000 Å, 50 ms/line, 32 A/D. One of the distinct features of an Octanethiol monolayer is clear in this image and that feature is the presence of domain boundaries of Octanethiol molecules. These are seen here as the slanted lines of tightly packed molecules.

BB-500 Å, 50 ms/line, 32 A/D.

BC-500 Å, 50 ms/line, 32 A/D.

BD-500 Å, 50 ms/line, 32 A/D.

BE- 500 Å, 50 ms/line, 32 A/D. Here we have easily the most clear image that I have ever taken of an Octanethiol coated surface. Except for the lower portion of this image, this image very clearly depicts the surface molecules and how they are arranged on the surface. The three previous images do a wonderful job of displaying this too but I think that this one does the best job, mainly because it has the least discrepancies and pollution caused by pits or other junk on the surface.

BF-500 Å, 50 ms/line, 32 A/D. This image displays a surface of lesser quality than the previous four but it still somewhat accurately depicts a thiol surface. There is an increased level of blurriness here possibly caused by a physical change to the tip near the end of the last image.

BG-500 Å, 25.0 ms/line, 128 A/D. This image displays an increased level of blurriness, most of which I believe can be attributed to the large pit in the upper portion of this image. This region could have also negatively the quality of the tip as it scanned across the uneven surface. However, beneath the general haze of the image, the molecules on the surface are faintly visible and are reminiscent of a typical Octanethiol surface.

BH- 500 Å, 25.0 ms/line, 128 A/D. There is an even larger increase in blurriness in this image and it's much harder to actually see the molecules on the surface here. A deterioration in the tip's quality is fairly evident from this image; there is little definition and distinction between the various features present here. I also believe that I might have accidentally bumped into the table whilst scanning, which caused the black streak in this image.

BI- 500 Å, 25.0 ms/line, 64 A/D. There is a slight improvement in the image's quality. There's a bit more distinction in the surface molecules here but the tip is still of questionable quality as this image is sort of streaky. BK-500 Å, 50.0 ms/line, 64 A/D. This image here is somewhat better than the previous one. I think what is mostly preventing this one from possessing a higher level of definition is the large discrepancy in height between the pit in the bottom middle and the high parts on both sides.

BL-500 Å, 50.0 ms/line, 64 A/D. There is a substantial improvement in the quality of this image. The surface molecules are very clearly present and distinct but there is still a bit of fuzziness present there as evidenced by the certain parts of this image which look like nonsense streaks.

BM- 500 Å, 50 ms/line, 64 A/D. Here the surface molecules are clearly present but their exact qualities are indistinguishable because streaks cover the image and create a blurriness which prevents us from being able to see more clearly into the image.

BN- 500 Å, 50 ms/line, 64 A/D. There is a similar problem here as the one in the last image. Furthermore the drift near the end prevented s from seeing the whole of the image anyway.

BO-500 Å, 50 ms/line, 64 A/D. Although this image has almost no junk or pits, the main problem with this image is the quality of the tip. It greatly obscures the image and prevents us from seeing how the molecules here form on the surface and how they group together.

BP-500 Å, 10 ms/line, 64 A/D. The tip's quality in this image is evidently fairly low as streaks plague the entirety of this image and prevent us from seeing clearly where one molecule distinctly ends and where another begins, especially so on the right side.

BQ-500 Å, 10 ms/line, 64 A/D. This image and the next one pretty much have the same level of quality as the last one and this is mostly because of the many streaks which blur the molecular structure of the image.

BR- 500 Å, 10 ms/line, 64 A/D.

BS- 500 Å, 50 ms/line, 64 A/D. This image is a fairly interesting one. I'm not exactly sure what exactly is causing it to look the way it does. There is a definite atomic structure present here but I think that the tip is creating streaks here that are giving it a structure like something I haven't seen before. Following this image, I used the range function to try to retract and then scan the same region.

BT-3989.75 Å, 100 ms/line, 8 A/D.

BU-500 Å, 50 ms/line, 64 A/D. There simply isn't much to this image. It's incredibly blurry and it would be a huge stretch to suggest that there is a molecular structure present here.

BV-500 Å, 50 ms/line, 64 A/D. Although this image is likewise pretty blurry, there is a bit more evidence that there are Octanethiol molecules present on the surface here. This can be seen mostly in the middle of the image as there is a diagonally packed structure of molecules which spans from the middle of the top half to the middle of the bottom half of this image.

BW-3898.75 Å, 100 ms/line, 64 A/D

BX-500 Å, 100 ms/line, 128 A/D. I think that this image typifies the deterioration of the tip's quality near the end of the day. The molecules are faintly present but the streaks seen here blur the majority of the image and prevent us from actually seeing anything clearly.

BY-500 Å, 25.0 ms/line, 64 A/D. The last two images here provide almost no insight into the surface molecules and are for the most part useless.

BZ-500 Å, 25.0 ms/line, 64 A/D.