CVD Synthesis of Monolayer MoS2 and WS2

Chris working in lab


Engineering and Applied Sciences


Project Summary

Thanks to PURM, I was given the incredible opportunity of working this summer as a research assistant at the Drndic lab. My research was mainly focused on transition metal dichalcogenides (TMD) monolayers, and ways to more efficiently synthesize usable samples. More specifically, the TMD’s of interest were MoS­­2 and WS­­2­, and the Drndic lab mainly used these monolayers for nanopore drilling. In turn, these nanopores would be used for DNA translocation.

My goal for the summer was to optimize the chemical vapor deposition (CVD) growth process of MoS­2 and WS2, so that the subsequent nanopore experiments could be run more frequently and efficiently. This entailed making miniscule adjustments to the growth recipe, in terms of temperature, carrier gas flow rate, time, and the preparation methods, all in order to achieve optimal growth. For my project, optimal growth was characterized as either achieving a continuous monolayer film, or triangular monolayer flakes large enough to be suspended and drilled into.

 The actual calibration and synthesis process was very time intensive, taking several hours to run one trial. In addition, since the materials I was working with required extreme care when handling, any little mistake could ruin an hour of preparation time. Furthermore, since the CVD process involved so many variables, slightly changing just one could lead to failure.

 Over my time at the lab, I learned to appreciate the delicacy of scientific discovery, as I realized first-hand how frustrating it was to spend half a day working on something only for it to fail without any obvious reason. Above all, not having any clear-cut guide to success, and having to piece together any available information in order to hopefully find a relevant way to improve an experiment, really challenged me to think beyond the science I was taught in the lecture hall and on paper. After ten weeks, I finally started to understand how tough a research career could actually be.

 I would definitely recommend PURM to anyone interested in pursuing a science-oriented career, as the ten weeks spent will provide one with some invaluable insights to life as a researcher, as well as confirm whether or not that life is suitable to one’s own interests. Personally, I don’t think I could have found a better way to spend my freshman summer.