Electrical and Computer Engineering (ECE) graduate student Jinmeng Shi has earned international recognition for her research into the semiconductor materials behind terahertz quantum cascade lasers (THz QCLs).
Shi, a Master of Applied Science (MASc) student co-supervised by ECE professors Dayan Ban and Zbig Wasilewski, received the Best Student Poster Award at the International Conference on Molecular Beam Epitaxy, held July 12–16, 2026, in Ann Arbor, Michigan. Her winning poster, “Towards Ultra-Smooth Interfaces in THz QCLs: Revisiting Si Doping in GaAs Grown on (411)A Substrates,” presented research aimed at addressing one of the challenges limiting the performance of THz QCLs.
These devices are built from many extremely thin layers of semiconductor material, which means even small variations at the interfaces between layers can affect how well the finished device works. Shi is investigating whether growing these layers on a different crystal orientation of gallium arsenide (GaAs) could produce smoother interfaces, while also tackling a complication with how silicon behaves during the growth process. Her experiments have identified conditions that allow for more predictable silicon doping while maintaining very smooth semiconductor surfaces — an important step toward growing and testing complete THz QCL devices using this approach.
Jinmeng Shi, MASc student in the Department of Electrical and Computer Engineering at the University of Waterloo.
For Shi, the research is a natural progression from her undergraduate studies in Materials and Nanosciences. She came to Waterloo through a joint program with Beijing Jiaotong University, spending two years in Beijing before completing the final two years of her degree at Waterloo. As her studies progressed, she found herself increasingly interested not only in understanding materials, but in what could be built with them. That interest brought her to ECE, where the MASc program gave her the opportunity to work directly with semiconductor materials, fabrication and devices.
Under the co-supervision of Ban and Wasilewski, Shi has gained experience across the research process — from molecular beam epitaxy and material characterization to cleanroom fabrication, device processing and testing. She says their mentorship has also changed the way she approaches experiments, particularly when results do not turn out as expected. Rather than viewing an unsuccessful experiment as a dead end, she has learned to examine the evidence, identify possible causes and use those findings to determine what to try next.
Shi plans to build on that experience as she completes her MASc, with the next stage of her research focused on applying what she has learned to the growth and fabrication of complete THz QCL devices. Longer term, she hopes to pursue a career in industrial research and development, bringing together her training in materials science and electrical engineering to work on semiconductor and optoelectronic technologies.