Week+of+12-8+and+12-9

December 8 I came in today and began scanning a sample of Octanethiol on Au(111) that Natalie had prepared for me. The first scan was very poor and noisy so I changed the tip after it. The next image, "AB", was much better than "AA". There was much more definition and visible features. I zoomed in to the bottom left corner. The Top half of this next image was poor because of the drastic differences in elevation between the edges and the middle. I tried zooming in to the middle region of the bottom half of "AC". This next image, "AD", was extremely noisy and had very low definition so I changed the tip after it. I approached with the new tip and got my best image so far. There were a plethora of features throughout the image and most were pretty well defined with the only drawback of this image being the large z-range with which I scanned. I hoped that the definition would improve and I would be able to see more and see more clearly at a lower level. I zoomed in to the top left corner of "AE" in hopes of doing this. This next image had a good amount of features and I wanted to see what would happen if I shot the laser at it. I brought the voltage of the piezo stack from 45.0 V to 5.0 V. Then i shot the laser for one minute. I let the sample cool for 5 minutes. Afterwards, I brought the voltage of the piezoelectric stack back from 5.0 V to 45.0 V. I believe that the laser altered the structure of the tip and made it much poorer than before. The after scan was nowhere close to the before image and on top of that, the quality of even this new area was terrbile. I stopped the scan halfway through and changed the tip. My first two attempts with the new tip failed so I changed the tip again. This same sequence happened another time. I finally was able to get a decent image, "AG". It was not the best image but it was not terribly bad. It was decent enough to investigate. I zoomed in to the bottom right corner of "AG". There were tons of features in this next scan. However, there was no atomic resolution. I did try shooting the laser at the image to view the affects on the features. I brought the voltage of the piezo electric stack from 45.0 V to 5.0 V. Then I shot the laser for 45 seconds. Afterwards, I let the laser cool for five minutes. It appeared that while cooling, the sample had expanded into the tip as noted by the now red light on the microscope that indicates a crashed tip. I tried retracting slightly with the STM's withdraw feature. Unfortunately, this kept crashing the sample when I tried zooming in and when I did eventually get the sample to approach, it was a different region completely. 12-8-11AA media type="custom" key="11644100" I should not have finished scanning this image. I should have simply stopped the image halfway through and changed the tip. I was messing around with the parameters of the STM program to attempt to get a better picture out of this first area but never successfully did. There is very little definition. Some features are faintly visible behind all the noise but with the low quality that I had, they were not worth investigating. 12-8-11AB media type="custom" key="11644102" This image was better in comparison to the previous image. The main reason for the poor definition of this image is due to the large Z-range that I had scanned with. There are features easily visible under the general orange coating of the entire image. I zoomed in to the bottom left corner of this image to hopefully find a more detailed image. 12-8-11AC media type="custom" key="11644106" The bottom half of this image is decent but the top half is simply incomprehensible. There are just extremes due to the drastic change in elevation in the surface of the gold. The bottom half shows a decent amount of noise but I wanted to eliminate this half of the image and scan the best looking part of the image even closer, the middle third of the bottom half. I zoomed in here. 12-8-11AD media type="custom" key="11644110" This image showed more fully the poor quality of the tip by the extremely high amount of noise. The features are not well defined in here and there appears to be no resemblance to Octanethiol in this image. I changed the tip after. 12-8-11AE media type="custom" key="11644116" This image showed a good amount of valleys underneath its orange coating.The main problem in this image is the high scanning parameter for the Z-range. Otherwise, there seems to be very little noise and the features look well-defined. I zoomed in to the top left corner. 12-8-11AF media type="custom" key="11644118" This image showed a little bit more noise than the previous one but it still was a decent image. I wanted to shoot the laser at it to observe what happened, but as I described above, this ultimately did not work. 12-8-11AG media type="custom" key="11644122" After changing the tip, I scanned this image. The left side showed a few features on the upper half but little of interest on the lower half. The right side had nothing noticeable in the top half but had a large showing of features in the bottom right. I zoomed in to this location. 12-8-11AH media type="custom" key="11644126" This image showed an extremely high amount of features and had my laser attempt been successful, we could have seen how all of these different features moved, expanded, shrunk, combined, or disappeared Unfortunately, that was not the case. December 9 I came in today and began scanning the same sample of Octanethiol on Au(111) from yesterday that Natalie prepared. The first scan was decently good and not terribly blurry. I zoomed in to a large region mainly on the bottom left corner of the image. The zoomed in image was decent for part of the scan but acted strangely throughout. I unfortunately closed the program while trying to close the picture I had just took of "AB" and could not zoom in to the top middle region I had planned on. I restarted the program and attempted to put all the parameters to what they were in the previous image but when I scanned it again, it was not the same image and had less definition than before. I stopped halfway through this image and recut the tip. The next scan, "AC" showed an interesting region in the top right corner. This region, "AD", seemed quite noisy but I wanted to see if I could get atomic resolution so I zoomed in aain to the right upper quadrant of "AD". "AE" was interesting because of its features but showed no real definition. I changed the tip after it. "AF" was blurry but I tried zooming in to the region in the middle and going towards the middle of the left side."AG" was not very good so I changed the tip. "AH" was very good and had a bountiful amount of features. I zoomed in to the region that had the most and diverse features on the right side. I will outline this region in a side by side image. I zoomed in to the bottom right quadrant of this image, "AI". There are organized lines throughout "AI" and it's unclear as to what these are. They appear somewhat in "AJ". I zoomed in to the region in the middle of the bottom half of "AJ". The lines of "AK" do not appear to be noise but look kind of like Octanethiol chains. I decided to try to shoot the laser at this image. I brought the voltage of the piezoelectric stack from 45.0 V to 5.0 V. I shot the laser for 45 seconds and it appears that the sample expanded and crashed during the shooting of the laser. I think I will need to increase the voltage of the piezoelectric stack for scanning to increase the distance between the scanning and the shooting of the laser. I have resolved to increase this to 90.0 volts. Since the tip crashed, I was unable to scan the same area that I had before the shooting of the laser and had to abandon the attempt. 12-9-11AA media type="custom" key="11644128" This image showed quite a bit of interesting features. The upper right corner seemed to hint at the lack of quality with this tip and it seemed more likely with this image that it was the quality of the tip that caused the problem rather than the parameters I was using. I zoomed in to a large region that was mostly on the left side of this image. 12-9-11AB media type="custom" key="11644134" This image showed a little bit more clearly the quality of the tip. However, i was deeply intrigued by the action on the top part of the image. My intention was to zoom in to this part of the image and try to discover at a smaller range more clearly what these things were. Unfortunately, I accidentally closed the program on the computer while closing the scan for "AB" that i had just saved. The scan after that fiasco revealed clearly the poor quality of the tip and I stopped the scan and changed the tip halfway through it. 12-9-11AC media type="custom" key="11644140" This image vaguely showed a large amount of features mainly in the upper right corner. That is where I eventually zoomed in. The bottom fourth of this image was simply scanned while I was adjusting parameters and the last three quarters of the image show the surface more clearly than it would have looked, even though it could have been better with a smaller Z-range. 12-9-11AD media type="custom" key="11644144" This image showed a reasonable amount of noise that could have been either Octanethiol or simply noise but I was unsure of it and decided to zoom in to the top left quadrant to clarify my assumption. 12-9-11AE media type="custom" key="11644146" This image showed much more clearly the poor quality of the tip and I changed the tip after it. The features' areas seem pretty well defined but there does not appear to be any Octanethiol in this image.

12-9-11AF media type="custom" key="11644158" This image showed a high amount of noise and just a bad tip. I should have changed the tip after this but tried to look for an improvement in a smaller region. I zoomed in to the region in the middle of the image and extending slightly out to the left. 12-9-11AG media type="custom" key="11644162" This image confirmed my assumption about the tip being poor and I changed it afterwards. The features were not well-defined and there was no real resemblance of the surface to any Octanethiol chains. 12-9-11AH media type="custom" key="11644166" This image showed a good amount of features and the quality of the tip cannot be truly determined by this image because of the large Z-range that I used to scan this image. 12-9-11AI media type="custom" key="11644168" The upper left corner of this image was especially bad but the top half of this image was mostly bad. The lower half showed some good features and some definition. The lines in this image could be seen as noise or as indications of Octanethiol chains. I tried to delve deeper in to the surface and zoomed in to the bottom left corner of this image.

12-9-11AH-AI media type="custom" key="11644368" 12-9-11AJ media type="custom" key="11644174" I think this image showed a little more clearly the lines throughout the image but I was still unsure about what these were. The features were not very defined but I wanted to clarify the issue regarding the lines. 12-9-11AK media type="custom" key="11644172" This image showed very well the lines that go across in patterns throughout the image. in the bottom part of the image they meet together in and arrow like manner going to the right. This actually appears to happen five times throughout the image as highlighted by the lines below. It is unclear as to whether these lines are simply noise or Octanethiol chains. Unfortunately, my laser attempt of this image also did not work. I have resolved, however, to use a higher starting voltage to maximize the distance between the sample and the tip when I lower the voltage of the piezoelectric stack. media type="custom" key="11644456"