Week+of+9-28+and+9-29

9-28-11 I came in today at 3:55 P.M. and began scanning a new sample of octanethiol on Au(111) that Natalie prepared for me. The first trial was not very good and showed no definition or features so I moved the scanning area then after that area showed about the same amount of definition and features (none), I changed the tip. After changing the tip, I scanned a region that was not very good so I moved the region to the left and took an image of this. This image was "AA". I zoomed in on the top right corner and scanned that region which was "AB". I scanned a total of five images with this tip before changing: "AA"-"AE". "AE" was not a very defined image so I changed the tip. After switching the tip I scanned four more images from "AE"-"AH". After "AH", I switched the tip and scanned two more images: "AI" and "AJ". These images were not very good and had a lot of noise and little definition. "AI" had clearer features than "AJ", but "AJ" had much more noise than "AI " and it was difficult to tell anything important from either of the images. 9-28-11AA media type="custom" key="10648354" "AA" was the first region that was good enough to finish scanning today. It started out badly but after adjusting some of the parameters of the software I got the image that you see above. This image, though not very defined, shows a large amount of valleys in the top half along with four valleys. This image had a lot of potential area that could have been scanned in a smaller area and at a higher resolution that could have shown even more distinctly the features and possibly the Octanethiol. 9-28-11AB media type="custom" key="10648358" In this image, I zoomed into the top right corner of the previous image, "AA". This image showed distinctly the hills and valleys of the surface. However, the high amount of noise prevents us from seeing any of the chains of Octanethiol

9-28-11AC media type="custom" key="10648364" This image is not as defined as the one before and has a little more noise than it. There are also less features but there are still many of them. The noise in this photo prevents us from seeing any Octanethiol on the surface of the gold. 9-28-11AD media type="custom" key="10648372" This image is a zoomed in image of the top right corner extending slightly past its borders of the last image. There is a significantly less amount of noise in this image. There are distinct valleys seen in this picture. There is a possible hill on the surface in the top right corner but we cannot be sure. Although there is less noise than before, there is still too much noise to see any Octanethiol on the surface. 9-28-11AE media type="custom" key="10648996" This image showed very few features and little definition. This is mostly likely due to a drifty tip and to noise.

9-28-11AF media type="custom" key="10648384" After, I changed the tip and took a general image to look for any regions with a large amount of features. This image showed a large amount of features throughout the entirety of it.

9-28-11AG media type="custom" key="10648396" This image is the zoomed in region of the middle of the bottom half of the previous image. I thought this region, with its high density of features and its large amount of contrast, was the most interesting and palpable region of the previous image. While scanning, however, the image experienced a large amount of noise and it is difficult to make out some features on the right side of the image in the top half. Several of the features are distinct such as the hill in the left bottom corner and the valleys that seem to almost wrap around it at a distance. We do not see any Octanethiol distinctly in this image. This could be due to a bad tip or to high amounts of noise. 9-28-11AH media type="custom" key="10648402" This image is extremely noisy and shows mainly valleys. It is difficult to make any assessments from this image because it has little definition and poorly defined features. There is also no clear Octanethiol on this surface. This is more likely affected by the high amounts of noise than a bad tip.

9-28-11AI media type="custom" key="10648416" This image has a lot of valleys that are not very defined. It is difficult to make out any information from this image because we cannot see any of the Octanethiol chains on the surface due to a lower amount of noise, compared to the past image, and bad tips. 9-28-11AJ media type="custom" key="10665226" This image shows a lot of noise and most likely a bad tip. It is hard to tell any important information from this picture because of its low definition and because of this we can look at this and be nearly certain that what we are seeing is noise and not the octanethiol chains. 9-29-11 Today I came in around 3:50 and began scanning the same sample of Octanethiol on Au(111) from yesterday. The STM would not approach the sample holder so I cleaned the sample holder with Ethanol and replaced the tip. After this I was able to actually get images. The second image I scanned, "AB", I decided to laser because there were several valleys and I wanted to see what would happen. I turned the voltage of the piezoelectric stack from 45.0 V to 5.0 V and shot the laser for 50 seconds. Then I let the sample cool for five minutes. After this cooling period was over I brought the voltage back up to 45.0 V and began scanning. The two images were of the same area. They showed the same images throughout. In the after image, "AC", it appeared that the valleys in general were becomer rounder. However, some of the valleys became more oblong after the lasering. I attempted to laser the image "AD" because there were a large amount of valleys in the top half of the image. I brought the voltage of the piezoelectric box once more from 45.0 V to 5.0 V. I then shot the laser for one minute and fifty seconds. I then let it cool for five minutes. Unfortunately, after raising the voltage back to 45.0 V, I was unable to scan and I even tried adjusting the voltage of the piezoelectric box to see if it would stat scanning and it did not. It kept bottoming out and crashing. I changed the tip after "AD" and took a general scan of an area to look for smaller regions with lots of features. This was "AE". I took three images with this tip and none of them was good enough to shoot the laser. "AG" was bit very defined and showed both a lot of noise and a drifty tip so I changed the tip after this image. After switching the tip, I took "AH" which showed a very interesting region in the top left half. "AI" was the enlarged image of this and it was not a high quality picture because of the noise in the lab and the poor quality of the tip I cut which was unable to show a great deal of definition. 9-29-11AA media type="custom" key="10688572" This was the first image that I finished completely scanning of the day. I used this image just as a general view of the area so I could zoom in and take an image of a smaller region with a good amount of features and hopefully see some of the Octanethiol. 9-29-11AB media type="custom" key="10688578" I zoomed in to the middle of the right side of the past image to scan this area.This image was quite noisy as one can tell by the streaks across the image. There is a high concentration of valleys in the upper left quarter of the image. Despite its low definition, I decided to shoot the laser at this image to see what would happen with the valleys. 9-29-11AC media type="custom" key="10688596" This is the after image of "AB" after I shot the laser at it for 50 seconds and let it cool for five minutes. The two images have the same area. One can tell because of the arc in the upper right corner and the region below it that juts out and looks like a reverse arrow. Also, many of the valleys that were in the first image are in the second image.The largest problem seen between the two images is that the region moved slightly to the right.It also looks as if the valleys have, overall, become slightly smaller. Also, more valleys seemed to have become more round in shape instead of more oblong. However, it was impossible to see any changes between the Octanethiol because the tip is too bad and there is too much noise preventing us from seeing a high amount of definition. 9-29-11AD media type="custom" key="10688582" This image showed a lot of valleys but not very much definition and so I decided to change the tip after this. I did not think there was much to gain from shooting the laser at this image.

9-29-11AE media type="custom" key="10688598" This image was just a general scan after changing the tip in hope of finding an area with a good amount of features and definition. 9-29-11AF media type="custom" key="10688610" This image was the zoomed in region of the upper left corner of the previous image. This image was extremely noisy as seen in the streaks across the image. The tip for this was also quite bad but I suspected that it was mostly due to the noise and so I tried to zoom in on the bottom left to right past the middle of the image to try to find something. 9-29-11AG media type="custom" key="10688614" This image confirmed the terrible quality of the tip. The image shows many streaks which are caused by both noise and bad tips. It's hard to observe anything in this image because of the low definition and the low amount of features available. I decided to change the tip after this image. 9-29-11AH media type="custom" key="10688616" This image was a general scan searching for a better smaller area to scan. The upper left corner showed a lot of valleys but also a couple hills and so I decided to zoom into that area. 9-29-11AI media type="custom" key="10688618" The scanning of "AI" proved unfruitful in its enterprises. The tip was poor and there was a lot of noise. There were were many features in this area but because of the low definition it was not worth shooting the laser at because there was no octanethiol that I could see. 9-30-11 On this day, I went to Quarknet and went over the first chapter exercises with Dr. Loughran, John and Paige. We tried out some of the features taught in chapter one in MATLAB and we decided on communicating any questions or problems online.