Week+of+9-14+and+9-15

9-14-11

I came in at about 3:45 p.m. today and began scanning a sample of octanethiol on Au(111) that Natalie had prepared for me. My first area I found was not very good so I moved areas and found two small areas within a large 200 nm x 200 nm area that had some definition. This was on "AA". After that Izoomed in to the upper right of that image to a size of 43.75 nm x 43.75 nm. I scanned that region and got some recognizable features in "AB". I then moved around 60 nm to the left and got some more features in "AC". "AD" was not a very good image and after it I changed the tip. After changing the tip and scanning I got another terrible image, "AE". I changed the tip again and scanned around searching for a good area for about 20 minutes and changing tips every five minutes or so after I saw a terrible scan coming. After all of this, I found a good area in "AF". It has many distinct features and I decided to shoot the laser at it. I brought the piezo stack power supply from 45.0 V to 10.0 V. Then I shot the laser for 50 seconds then let it cool for two minutes. I took a post image and it was clear that "AG" was the same area because it had many of the same features as the pre-image. I left at 6:15 p.m. today. Overall, it was not a very good day of scanning until the final two images that I scanned. These were most likely due to bad tips rather than the sample. media type="custom" key="10468428" media type="custom" key="10519758" 9-15-11 I came in at about 3:35 today and began scanning the same sample of Octanethiol on Au(111) from yesterday. I tried scanning and got nothing good so I changed the tip. I did this a total of 7 times and moved the sample puck around 6 times to try and find a good image. I did not successfully get an image or area worth finishing until 4:57. This first image was still awful. I tried scanning for another region but I was unsuccessful so I changed the tip again. I fully scanned four images today. None of these images was good or had any definition. I think these awful results today were due to bad tips and a bad sample. The sample most likely deteriorated in quality over night and the tips were not the sharpest. Hopefully images improve next week when I return. 9-15-11AA media type="custom" key="10573440" This image has bad definition and essentially no recognizable features. It also has a lot of noise 9-15-11AB media type="custom" key="10573452" This image is even worse than the one before because it is even noisier and there is such a contrast in the topography that it is near impossible to see anything.

9-15-11AC media type="custom" key="10573460" This image is very noisy and does not have that much definition but has two recognizable features: the valley in the lower left and the hill in the upper right. 9-15-11AD media type="custom" key="10573472" This image has very little definition and one valley in the middle right. There is a lot of noise throughout the image and it is hard to see very much.