Week+of+11-3+and+11-4

11-3-11

I came in today and set up the STM and the computer because they were unplugged and in their cases from when Natalie used them last week in her presentation. The first image had a nice looking area on the top half. However, the second image showed the poor quality of the tip so I changed it. The second tip I tried to use proved to be terrible as well so I stopped the first scan with it and changed the tip. The third tip I tried also gave a terrible image."AB" was bit very good but it was the best image I have gotten since AA. I moved the sample after "AB" and tried scanning again. This second image was better. I zoomed in to the middle left side of it. This image showed another bad tip. Overall, today was not a very good day. I think the poor quality of these images was mostly due to poor tips. 11-3-11AA media type="custom" key="11166282" This image was mostly blurry due to the bad tip and the parameters used while scanning this image. I did not scan with a very small Z-range. There are plenty of features visible in the top half of this image. I zoomed in to the top middle portion of this image. 11-3-11AB media type="custom" key="11166292" This image showed few visible features and no real definition. I tried to reconcile this image by zooming in to the middle portion of this image. The following scan failed and somehow retracted during the scan. I did not think the tip was too bad so I simply moved the sample and re-approached. 11-3-11AC media type="custom" key="11166298" This was the image i scanned after I approached from a new area on the sample. There are clearly a large amount of features on this image. There is little definition on this image though. I zoomed in to the darker region on the left edge in the middle. 11-3-11AD media type="custom" key="11166312" This image showed some features but more importantly showed a large amount of noise. This was not a very good image and we cannot really gather any useful information from this image. 11-4-11 I came in today at 3:40 and began scanning the same sample from yesterday of Octanethiol on Au(111). The LED panel on the piezoelectric power supply box is no longer working properly. It flashes on birghtly then completely fades away in a matter of seconds. It took for a while for the STM to correctly approach for the first time today. The first image was terrible. The second image was also very poor so I changed the tip afterwards. The STM kept beginning scans and then would bottom out or crash about a quarter way through the scan. This happened five times before it successfully scanned a full image. This next image, "AC", was great compared to the other two. I zoomed in to the bottom right corner of it. "AD" was not very great but showed a pretty decent amount of features so I decided to shoot the laser at it. Since the piezoelectric power supply box was not working properly, I could not utilize it in my laser process. I shot the laser for one minute and then let the sample cool for five minutes. I then scanned and the after image was of about the same quality as before. It was very clear that these two images were of the same region, just moved slightly up and to the right. The poor quality of the first two images is most likely attributed to the poor quality of the tips and possibly the STM acting strangely. The last three images showed a slightly improved tip, but this tip was also not too great. 11-4-11AA media type="custom" key="11190890" This image showed what could have possibly been some features in the middle part of the bottom However, the poor quality of the tip made it extremely difficult to discern the true nature of the image. I should have changed the tip right after this image, but I foolishly did not. 11-4-11AB media type="custom" key="11190896" For this image, I approached again after retracting the sample after the mishap in the previous scan. This scan confirmed fully that the previous image had a terrible tip and I changed the tip afterwards. 11-4-11AC media type="custom" key="11190900" This image showed an improved tip from the previous two images. It showed a large amount of features, parceled out in concentrated groups throughout the image. There is no visible Octanethiol in this image but the features are quite evident.

11-4-11AD media type="custom" key="11190906" This image did not show a very high amount of definition but did provide a good amount of features. As the best image of the day, I decided to shoot the laser at it to see what would happen with the after image.

11-4-11AE media type="custom" key="11190920" 11-4-11AD-AE media type="custom" key="11191118" The Arrows in this side by side view simply show how the scanning region has moved between the before and after images. A- The valley to the left of A in the before image is less defined than the same region in the after image. There seems to be a large amount of noise across this valley that is not as present in the after image. B- This region is to the right of B. It, like A, shows a larger amount of noise in the before image than in the after image. This region also increased in size by a large amount. It seemed to have increased in a direction towards region A. C- In the before image, this region to the left of C is oblong and very noisy. In the after image, this region is more circular shaped and seems to have a significantly less amount of noise than the before image. D- This region, left of D, seems to have about doubled in size from the before to the after image. It is not like the other regions because it does not seem to have become more defined. E- There are two separate regions diagonally below E in the before image. In the after image, these two regions have joined together excluding the thin, faint line through the middle. Also, there seems to be less noise in this area in the after image. F-The region to the left of F in the before image is shaped slightly like an oval. In the after image, it is shaped sort of like a triangle. It does not seem to have become more defined but it also does not appear that it had decreased in definition. G-The region to the left of G in the before image is longer than the comparable region in the after image. It does not seem to have lost or gained a significant amount of definition from the before to the after image. H-The region to the right of H in the before image is shaped like a triangle. It seems like a pretty well defined area. In the after image, the definition appears to have decreased and the region looks more like an upside-down heart. Overall, I believe that the definition improved from the before to the after image, despite the occurrences where it did not. I think that the heat caused by the laser could have eradicated any unwanted junk from the surface and could have possibly sharpened the tip and subsequently made it a better tip.