UNIVERSITY PARK, Pa. — Paul J. Simmonds, associate professor in the Department of Electrical and Computer Engineering at Tufts University, will present “Tensile-strained self-assembly: Nanoscale stretching for novel quantum light sources” as part of the Penn State Department of Materials Science and Engineering’s (MatSE) 590 seminar series. The talk will be held from 3:05 to 4:20 p.m. on Thursday, Oct. 23, in 112 Kern Building on the University Park campus.
“Tensile-strained quantum dots are optically active, defect-free nanostructures,” Simmonds said. “Quantum dots (QDs) have been used as the basis for a wide range of optoelectronic devices. Large tensile strains allow us to tailor band structures for applications from tunable infrared emitters to entangled photon sources.”
Simmonds will present a robust approach to QD self-assembly that addresses longstanding challenges in synthesizing defect-free, tensile-strained (stretched) QDs on (111) surfaces — a specific crystallographic plane used for growing other materials. Using molecular beam epitaxy — a material deposition technique that builds crystal films layer by layer — his team has developed a reliable and controllable method for growing these highly symmetric nanostructures across multiple material systems.
His presentation will highlight experimental data demonstrating the promising properties of these QDs for use as deterministic single- and entangled-photon light sources. The results suggest that tensile-strained self-assembly represents a powerful new tool for the synthesis of highly symmetric QDs and the development of novel quantum materials.
Simmonds’ interdisciplinary research combines semiconductor physics, molecular beam epitaxy and nanostructure engineering to advance the development of quantum materials and optoelectronic devices.
In recognition of his contributions to the field, Simmonds has received the 2018 North American Molecular Beam Epitaxy Young Investigator Award, the 2024 Charles Hatchett Award and a National Science Foundation CAREER Award. He is also a senior member of the Institute of Electrical and Electronics Engineers (IEEE).
Simmonds earned his doctoral degree in semiconductor physics from the University of Cambridge in 2008, followed by postdoctoral appointments at the University of Minnesota, University of California, Santa Barbara and Yale University. He later managed the Integrated Nanomaterials Laboratory at University of California, Los Angeles, and chaired the IEEE Photonics Society chapter. Prior to joining Tufts University in 2023, he held faculty positions at Boise State University and a joint appointment with Idaho National Laboratory.
MatSE 590 is a seminar series that features speakers from academia and industry on various topics in materials science and engineering. Support for MatSE 590 is made possible through the generous contributions of industry partners in the Friends of MatSE program.
For more information and a list of upcoming speakers, visit https://www.matse.psu.edu/graduate/graduate-resources/590-seminars.