Week+of+2-25-2013

2-27-13 I came into the lab today and worked with Jolai on scanning a sample of Au(111) coated with Octanethiol. Matt informed me that the scope was at the welder and that it will be up and running in the lab by this friday so I can begin using it and testing it next week. After about 45 minutes of fiddling with the scope, the tip was finally able to approach. I forced the sample to crash into the tip and then backed the tip up a few steps and it worked. I mainly just tried to scan around and to get some detailed images of the surface.

AA-2.72 µm, 500 ms/line, 1 A/D AB-2000 Å, 300 ms/line, 8 A/D AC-2000 Å, 300 ms/line, 8 A/D AF-2000 Å, 300 ms/line, 8 A/D Not much can be seen in any of the pictures from today concerning the structure of Octanethiol molecules in any of these pictures. Much of the images are filled with junk and noise, caused most likely by a poorly cut tip. It was a very disappointing day of scanning.

2-28-13 Today in the lab, Matt and I cleaned up the room and began setting up the new scope as it was finally ready. First I cleaned off the top of the yellow box pictured below that houses a scope that has not been used for a very long time. Then I cleared out the inside of the scope that I used all last semester and cleaned the top off it so that it could be moved off of the isolation table and on top of the yellow box.

After that, I cleaned up the rest of the work space and got rid of all of the trash in the room which cleared up a great deal of room on the desk and on the isolation table. Pictured above are the BNC inputs which will be connected to the electronics system to control the X, Y, Z offsets and slopes as well as the gain of the scope. The black and red cables on the right side connect to the Peltier device which sits beneath the circular copper block. The cold side touches the copper block and cools it while the hot side sinks with the rest of the structure and the entirety of the structure will be placed inside a bucket full of ice to regulate the temperature of the structure and to prevent it from overheating. The black box above is the box that powers the Peltier device via a BNC cable. The knob pictured on the right side of the black box controls a potentiometer. Lower resistances allow for greater and faster temperature changes. Using the lowest resistance, we were able to get the copper block on the scope down to 2.0 degrees Celsius, which is a promising sign for our future experimentation in being able to heat and cool the sample quickly. The darker brown cable cable on the left side pictured above and below is the thermocouple. The square plate seen on the front of the scope is screwed on to the rest of the scope. To place or change a tip, one must unscrew this part of the scope. The small opening seen on the top of the scope is where the resistor will be placed to heat the sample.

Pictured below are the tubing and the cage that lead to a Nitrogen gas tank in another part of the lab. Matt and I spent about 30 minutes rewiring the tubing for this system. The brown copper tube pictured above will leak nitrogen into the scope and a glass cover will be placed over the opening on the top of the structure. This scope will operate under nitrogen to minimize interference from air molecules.