Week 4: Nice and Steady

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Sunday, June 21, 2015


Veronica Martinez-Vargas

First and foremost, the target substrate is ready! It was finished on Friday. I spent the other days mostly working on the material exfoliation process. On Monday, Teresa and I analyzed more I-V data and obtained the charge mobility of a silicon transistor. Tuesday, Wednesday, and Thursday I practiced exfoliating flakes onto a Si/SiO2 (Silicon/Silicon Dioxide) substrate. This was a nice, sticky experience. The purpose of this process is to get a few monolayers sample of MoS2 since we want the flake to be about ten nanometers in thickness. I was given a block of MoS2( Molybdenum Disulfide), three pieces of blue (scotch-like) tape, two tweezers, and three Si/SiO2 substrates. The first step was to tab the block on the first tape to get some MoS2 chunks on it. Once I got some nice small chucks on there, I folded the tape in half and pull it off, then stuck the tape to a substrate, made sure some material was transferred and peeled it off. Next, I stuck that tape onto another tape, and went back and forth for about some 10 minutes before sticking the second tape onto another substrate. I repeated the same steps with the third tape and substrate. All of this was necessary to get nanometer thick flakes. After each transfer to the substrate, I characterized the flakes size and spread using the optical microscope. Dr. Arvind Balijepalli lead me in understanding the purpose of this procedure and suggested that I figure out the efficiency of the procedure by obtaining a quantitative analysis, as well as figuring out a way to optimize the number of qualifiable flakes in a certain area. I can’t wait for next week, we are going to start working with our target substrate.

Outside of work, I’ve had a steady, relaxing week. Last Friday, I attended a dinner at Clyde’s restaurant with all the SPS interns and SPS executive council. This was followed by a nice tour of the monuments. Sunday, was a relaxing day that ended with a much-needed sushi dinner at Sushi Para with some members of the gang. 

Veronica Martinez-Vargas