Peddie EXP 2017

My lab during an ice cream outing at Toscanini's :) This week, I proceeded to attempt converting a raw SEM image into a binary array. Although the code successfully segmented the images and calculated the centroid coordinate points, the order in which the coordinates of the centroids were listed in the data table was incorrect. Upon research, I realized that the root of the problem was the method in which MATLAB’s ‘centroid’ function saves the coordinate points of the centroids. This led to incorrect calculations of the state values, and thus an inaccurate binary array. To overcome this problem, I manually rearranged the coordinate points so that the y-coordinates would be in the correct order of descending posts from top to bottom (rows) and left to right (columns). As a result, the code produced a binary array with the correct numerical values, as well as a visual representation identical to the block copolymer pattern shown in the raw SEM image. ...

This week, I have finally finished my project on writing a code to convert a visual representation of an SEM image into a binary state array. With the coordinate points of the post centers I’ve found by using the tool ‘centroids’, I continued to write a code that computed the x and y coordinates of the states (the positions between each two adjacent posts). This way, I could inspect the area surrounding the state to determine whether there is a connection or not between the two posts. This was fairly easy, as it was simply taking the coordinate points of the posts and averaging them to find the midpoint between each two adjacent posts. The tricky part was dividing the cases into two: one where the state was located between two left-right posts and two top-bottom posts. After I figured this part out, the rest was fairly easy, and I was able to obtain all 351 coordinate points of the states. Now that I knew the coordinate points of the states, I wanted to cut out small squares...

This week, I’ve been working on a new coding project, as well as wrapping up the lab procedure I started on week 2 with template fabrication. I also learned how to examine and take photos of a block copolymer pattern with a scanning electron microscope (SEM). When the solvent annealing was over, I removed the wafer from the solvent, transferred it into a little container and brought it over to another lab with a machine that worked as both a SEM and an electron beam lithography tool. Because the machine is kept at a vacuum state, I had to first vent the chamber by introducing air, and pump the air back out through evacuation once I inserted the wafer. Once it was ready to go, the computer connected to the SEM displayed the magnified image of the patterns on the wafer. Much like adjusting the resolution of the image you see through the lens  of an optical microscope  by turning the knob, there were multiple variables I had to adjust to find the perfect resolution of th...

This week, I applied the techniques I’ve only read on paper to the real lab. I learned how to manually fabricate a template of block copolymers through thermal and solvent annealing. My grad student, Brian’s research actually intertwines electrical engineering and materials science. So the main lab he works in, which is shared by other materials science researchers, happens to be a good five minute walk from Dr. Berggren’s lab. My grad student tells me that because of all the snow during the long winters in Boston, most of the buildings of MIT are connected somehow - which means I could get from the electric engineering department to the materials science department without setting a foot outdoors. We share the lab with people from another lab that also work on the research of block copolymer self assembly. Brian showed me where what was, and taught me how to create a block copolymer pattern. Firstly, I spin coated the sliced silicon wafer with the PDMS (polydimethylsiloxane) ...

My first week at MIT has been exciting and full of new challenges. On my first day, I stumbled into building 36, also known as the Research Laboratory of Electronics (RLE) building, slightly overwhelmed and quite nervous. Dr. Berggren’s lab was located on the second floor, and was pretty easy to locate among the many labs in the building, being the first lab in the hallway. It was 9AM on a Monday morning, and only a few other members in the lab were present. The postdoctoral fellow that I had been contacting via email soon arrived and instructed me to go to the Atlas Service Center to get my ID, leaving me with a map of the campus (he had to run to a meeting). I got my ID, and found my way back to the my information center of the RLE department, where the guy at the desk inputed my information into the system and gave me a little welcome package. I went back to the lab, where Dorothy, a sweet lady and the administrative assistant of Dr. Berggren’s lab, tagged me onto the lab emai...