From Dislocations to Luminescence: Epitaxial Strategies for Infrared Optoelectronics
Kunal Mukherjee
Assistant Professor, Materials Science and Engineering
Stanford University
Abstract: Integrating dissimilar semiconductors on a single crystalline platform could enable the next generation of devices for optical communication and sensing. Materials such as III–V and IV–VI semiconductors, when epitaxially grown on silicon, offer distinct optoelectronic properties that expand the capabilities of this scalable system. However, bridging the structural and chemical mismatches between these crystals while minimizing defect generation remains a significant materials science challenge.
In this talk, I will present new insights into how dislocations arising from integration severely limit the performance of III-V telecom lasers. I will then show how we employed alloy hardening and quantum dots to realize dislocation tolerant lasers grown on silicon. Building on lessons from III–V integration, I will highlight emerging opportunities in IV–VI semiconductors such as PbSe–SnSe, which are inherently more tolerant of defects, enabling efficient mid-infrared light emission for sensing applications. I will also discuss our efforts to engineer crystalline–crystalline phase transitions in these semiconductors for reconfigurable photonic circuits. By advancing our understanding of crystal defects in mismatched epitaxy, we identify new pathways for scalable integration of optoelectronic materials.
Bio: Kunal Mukherjee is an assistant professor in the Department of Materials Science and Engineering at Stanford University. His research focuses on compound semiconductor thin film synthesis and defect science. He received a B.Eng. in Electrical Engineering from Nanyang Technological University, an M.S. from the National University of Singapore, and an M.Eng. and Ph.D. in Materials Science and Engineering from MIT. Before joining Stanford, he served as an assistant professor in the Materials department at UC Santa Barbara (2016-2020) and held postdoctoral appointments at IBM and MIT. His work on epitaxy and crystal defects has been recognized with an NSF CAREER award, the Corbett Prize at the International Conference on Defects in Semiconductors, the Young Scientist Award at the International Symposium on Compound Semiconductors, and the Young Investigator Award at the North American Molecular Beam Epitaxy conference.
