Optimizing the Synthesis of MoS2 and WS2 Monolayers

Niels working in engineering lab




Project Summary

The goal of my project was to determine what conditions and techniques optimized the growth of molybdenum disulfide and tungsten disulfide monolayers. These materials are known as transition metal dichalcogenides (TMDs), and they offer increasingly unique electrical and optical properties as they become monolayers. At only a few atoms thick, these “2D” materials can act as photodetectors and a medium nano pores.

Graduate students in the lab had already created a procedure for creating these monolayers, but it was far from optimized. The monolayers are grown on silicon dioxide chips by coating the chips with solutions containing either molybdenum or tungsten, and then heating them in a furnace with sulfur pellets to facilitate the sulfurization of the chips. Several factors go into the success of growing the triangle shapes “flakes” of monolayer, including growth time, growth temperature, and the concentration of the coating solutions.

Since the growth of these monolayers is such a new field, much of the experiments done are trail and error. Every day we would grow multiple batches of flakes, changing different variables and recording the successes of the trial. By the end of the summer we had developed a new procedure using methods new to the lab that resulted in large and useful MoS2 and WS2 flakes.

Through this experience I learned much about nanotechnology fabrication and applications, but to me what was most important was experiencing what daily life was like for a physics researcher. I came to understand the interpersonal dynamic of a physics lab, how lab meetings operate, and how manage my own time regarding my research. As a potential physics graduate student, this glimpse into what five or six years of graduate school research would be like is invaluable in helping shape the course of my education.