Week+of+11-17+and+11-18

11-17-11

Today, I came in a at 3:40 pm and began scanning a sample of Octanethiol on Au(111) that Natalie prepared. The sample holder seemed to have tipped slightly to the left at about 75% into the scan. However, it appeared to be the same region. I tried zooming in to the middle area with several features. The next scan showed the bad tip more vividly than in the first one and I stopped scanning and cut a new tip. The next attempt also showed a terrible tip and I once more stopped the scan and changed tips. The image after this was blurry but a little better than the previous two attempts. I zoomed in to the middle right area where the majority of the visible features were. This next image, "AC", had a lot of streaks and was very blurry. I changed the tip afterwards. "AD" was pretty good. I zoomed in to the upper left corner for the next image. "AE" was also very good. I decided I would shoot the laser at it. I brought the voltage of the piezoelectric stack from 45.0 V- 5.0 V. Then, I shot the laser for one minute. I let it cool for five minutes. Then I brought the voltage back up to 45.0 V. The after image looked nothing like the before image. 11-17-11AA media type="custom" key="11377018" This image showed a good amount of features but not a very high amount of definition. However, the parameters used to scan this image did not allow for me to be certain of the quality of the tip. I hoped that a zoomed in image would provide better knowledge of the image and the tip quality. I tried zooming in to the main middle region but the following scan showed the terrible quality of the tip and I stopped it about 25% of the way through after adjusting parameters. I changed the tip stopping the image.

11-17-11AB media type="custom" key="11377022" This image also could not provide me with certainty about the quality of the tip. There was a small amount of features and I decided to zoom in to the middle of the far right side. 11-17-11AC media type="custom" key="11377028" This image showed me the poor quality of the tip. It's possible that the diagonal streaks in the large middle region could have possibly been Octanethiol. However, the top of the image showed an excessive amount of streaks and provided me with enough necessity to change the tip. I did so after finishing the image. 11-17-11AD media type="custom" key="11377034" This image's parameters did not allow for a high level of certainty regarding the quality of the tip. the large valley through the middle of the ride side of the image prohibited me from scanning with a low Z-Range. I zoomed in to the top left corner. 11-17-11AE media type="custom" key="11377038" This image showed a decent tip and some definition. The features are mostly well defined. I decided to shoot the laser at this image. 11-17-11AF media type="custom" key="11377042" This after image looked absolutely nothing like the before image. It's entirely possible that I may have slightly moved the sample holder by bumping into something connected to it. This image showed the decrease in quality between the tip of the before and after images. Light used to heat the laser does indeed seep through the gold and reaches the tip. This could possibly worsen the quality of the tip and make it more blunt than sharper.

11-18-11 I came in today at 3:35 and began scanning the sample of Octanethiol on Au(111) from yesterday that Natalie prepared. The first tip I used was not giving any recognizable parts so I changed it about a quarter of the way through the first scan. I re-cut the tip and tried scanning again. The same thing happened with this tip. I re-cut the tip again and tried scanning again. This time the scan showed a little bit more detail. However, it was still a poor image and I changed the tip afterwards because of the blurriness of the scan. I changed the tip and cleaned the STM and sampleholder. The next image I took was a huge improvement from previous images. The upper left corner of this image showed the promised features, I zoomed in on "AB" in this upper left corner. However, during the scan, the sample holder retracted by some small amount and bottomed out. This region was a very good region so I tried to just reapproach and it did indeed work. However, the second time through, through my own fault, I accidentally moved one of the wires connecting the piezo stack to its power supply. This moved the sample substantially and it bottomed out. I could not reapproach and get the same area. I did manage to scan a new area with this same tip, which I finished scanning. However, this scan showed a bad tip and I changed it afterwards. I then took an image, "AD", which was decent. I zoomed in to the rmiddle region in the upper left quadrant of this image. "AE" was not very well defined at all. It was mostly blurry and had a lot of streaks. I tried zooming in to the bottom right corner of "AE" because I had very little tim e left and I would not have been able to start a new series of scans, and I wanted to see if I would be able to get anything at that small of a scanning region.This image was a prime example of what I are not looking for in my research. 11-18-11AA media type="custom" key="11377048" This image showed nothing of value. There was a region in the bottom left quadrant that could have had something of bleak resemblance to features. However, I should not have finished this image. I should have stopped it less than halfway through and changed the tip. 11-18-11AB media type="custom" key="11377052" This image showed some very good features in the top left image and could have shown more features had I adjusted the parameters for scanning earlier. I tried zooming in to the top left corner but as described above, this ultimately did not work. 11-18-11AC media type="custom" key="11377056" This image showed no features, no definition, and a terribly poor tip which I changed after. 11-18-11AD media type="custom" key="11377058" This image could have been much better if I had adjusted the scanning parameters earlier in the image. It shows a large amount of features in the top half. I zoomed in to the top left corner. 11-18-11AE media type="custom" key="11377060" This image clearly showed a bad tip and not really much definition in regards to the features. The streaks caused by the tip obstruct the ability to truly recognize any real definition of this image. However, because of a lack of time, I just decided to see what would happen if I zoomed in to the bottom right corner. 11-18-11AF media type="custom" key="11377074" This image was absolutely awful. It showed streaks throughout and no definition on the surface or in relation to the features at all. This is a great representation of what I do not want to find in my research.

I updated my PowerPoint to include any new before and after images that have occrured since the last PowerPoint.