Week+of+4-15-2013

4-17-2013 I began the day by scanning a sample of C-60 on gold. This time it was prepared by being placed in a saturated solution in Acetonitrile for 10 minutes. AQ-500 Å, 32 A/D, 300 ms/line. This image, for the middle third, has the appearance of atomic resolution but a closer look at the rest of the image suggests otherwise. The bottom part of this image is rife with streaks and it looks as if the rest of the image is full of these streaks caused by the tip dragging across the surface as if it's getting caught on it. I moved the scanning region down and to the right. AR-500 Å, 32 A/D, 300 ms/line. In this image, there does not seem to be much definition. The majority is plagued by horizontal streaks with make it look like nonsense and as if no monolayer is present. The bright clumps are most likely large groupings of C-60 but it is difficult to say for sure and even more so to determine any of their surface chemical properties because terrible streaks prevent us from seeing anything with any real certainty. I retracted the tip afterwards. AS-3718.88 Å, 32 A/D, 300 ms/line. This image appears to be a little bit better than the previous two. There is a bit more definition in this one as can be seen by the somewhat distinct steps in the surface in the lower left corner. There are also fewer streaks present in this image. I zoomed into the bottom left corner. AT-1000 Å, 32 A/D, 300 ms/line. Here we have a fairly good representation of the C-60 molecules clumped up in groups on the surface, though according to Matt, they are supposed to group together in larger collections than what is seen here. I zoomed into the middle of this image. AU-500 Å, 32 A/D, 300 ms/line. Part of this image appears to be fairly well defined and appears to show a somewhat properly aligned surface structure. However, some areas of this region are plagued by blurriness caused by streaks. I scanned the region again. AV-500 Å, 32 A/D, 50 ms/line. This image is full of blurriness and also does not appear to be of the same region. I think that this is probably due both due to the nature of the surface and of the tip which are both causing it to sort of drag across the surface as it scans. I moved the scanning region up and to the right. AW-500 Å, 64 A/D, 200 ms/line. This image is a lot like AU in that part of it is well-structured and part of it is blurry nonsense. The C-60 molecules typified by the brighter spots in this image are close together but not in a way that suggests that they are grouped together chemically. I zoomed out and moved up. AX-500 Å, 64 A/D, 200 ms/line. This image has fairly decently defined boundaries between the different steps in the gold surface but the streakiness of the image prevents us from seeing the C-60 molecules on the surface. I moved left following this image. AY-1000 Å, 64 A/D, 200 ms/line. This image shows a similar level of quality to the previous one, suggesting that the tip has not been altered from its previous state of fairly low quality. There seems to be a faint structure under all of the noise as is best pictured in the center of this image but it is almost nonexistent in the rest of the image. I moved the scanning region up afterwards. AZ-1000 Å, 32 A/D, 300 ms/line. This image is rife with streaks from the tip interacting with the surface in unwanted ways. The step boundaries in this image are less defined and distinct than in the previous few images and this image lacks any sort of possible molecular composition on its surface. I retracted the tip after. BA-3718.8 Å, 32 A/D, 300 ms/line. This image displays fairly clearly a large amount of C-60 molecules on the surface, especially in the top and bottom thirds. However, based on the molecules present here, there doesn't seem to be any sort of structure in how these C-60 molecules arranged themselves. Matt informed me that they should be forming in a hexagonal pattern so this is fairly interesting. Perhaps this could be caused by leftover solvent on the surface preventing the C-60 molecules from bonding and arranging properly. I zoomed into the bottom left. BB-1000 Å, 32 A/D, 300 ms/line. This image is fairly intriguing. There is almost definitely a molecular structure on the surface picture here but it is so faint that it is difficult to gain any real knowledge from it. It's very fuzzy throughout the whole image and this prevents us from seeing the discrete molecules and how they are arranged. I zoomed into the bottom right of this image. BC-500 Å, 32 A/D, 300 ms./line. This image is a lot like the previous one. A definite molecular structure is present but it's exact properties cannot be distinguished because of the general fuzziness that covers the entire page caused by the tip's lack of sharpness. 4-18-2013 I came into the lab and began scanning a sample of C-60 on gold. This sample was dip cast for 30 seconds in saturated Tetrahydrofuran. AQ-2000 Å, 32 A/D, 200 ms/line. I moved the scanning region to the left. AR-2000 Å, 32 A/D, 200 ms/line. I turned the set point up from 200 to 1000 then I scanned the same region. AS-2000 Å, 32 A/D, 200 ms/line. I moved down after this image. AT-2000 Å, 32 A/D, 200 ms/line. I moved the scanning region to the right. AU-1000 Å, 32 A/D, 200 ms/line. I tried to improve the quality of this image by increasing Bias then scanned the same area. AV-1000 Å, 32 A/D, 200 ms/line. I zoomed in to the middle of this region. AW-500 Å, 32 A/D, 200 ms/line. I put setpoint back down from 2000 to 200 and scanned again. AX-500 Å, 32 A/D, 200 ms/line. I scanned this same image again. AY-500 Å, 32 A/D, 200 ms/line. I tried to improve the image quality by switching the bias polarity from positive to negative then scanned again.

BA- 500 Å, 32 A/D, 200 ms/line. I moved the scanning region up after it. BB-500 Å, 32 A/D, 200 ms/line. I moved the tip to the left. BC-500 Å, 32A/D, 200 ms/line.

Unfortunately, I was not able to obtain any real applicable results from my day of scanning. When I had originally arrived in the lab, Matt had informed me that he was scanning earlier and that the quality was less than average, so I had not expected much from this sample. He also explained that his sample preparation was probably worse than usual. The images were all full of noise and streaks due to the sample and probably also due to the tip. A new type of sample preparation will be utilized the next time I come back into the lab and hopefully it will yield better results.