Experimental Interrogation of Exciton Dynamics within One-Dimensional Semiconductor Quantum Materials

Washington University, Saint Louis MO

Investigators

Abstract

Technical. This project utilizes and combines synthesis expertise with unique optical spectroscopic measurements, to create novel electronic/photonic materials, and to seek greater understanding of the chemical roles that internal and surface compositions as well as capping ligands play in influencing quantum wire photoluminescence (PL) lifetimes, quantum yields, and intensity intermittency. Materials to be explored include CdSe, CdTe, InP, and InAs. The research approach includes: determination of the origin and mechanism of the PL intensity fluctuations recently observed along entire quantum wells (QWs); measurement of exciton lifetimes and relaxation processes within single QWs as a function of material uniformity and surface composition; characterization of variations in the potential energy and the energetics of trap sites along single QWs by recording spectra and PL lifetime data as a function of temperature; and probing exciton diffusion along the long axis of single QWs. Non-Technical. The project addresses fundamental research issues in a topical area of electronic/photonic materials science having technological relevance. There is potential that the research could substantially impact the development of novel electronic devices and sensors. Participation in this research program will be a primary foundation for the education of graduate students with a significant role for undergraduates. The PI will continue to bring students from underrepresented backgrounds into his group to enhance their science education. He is active in three programs (including co-founder of a minority outreach research program) that strive to expose young minds to the wonders of science and independent research. The integration of coursework learning and research has been found to have a very significant impact on the retention of students in science, and this approach will continue to be emphasized.