Inter-American Materials Collaboration: Correlating Erbium Structure with Host Geometry in Doped Silicon Nanocrystals and Nanowires

Texas Christian University, Fort Worth TX

Investigators

Abstract

This Inter-American Materials Collaboration research focuses on fundamental investigations of rare earth-doped silicon nanocrystals and nanowires through an exchange of junior scientists, with directed interdisciplinary research training, between the groups of Jeff Coffer of the Texas Christian University Department of Chemistry and Leandro Tessler of the Department of Applied Physics at the State University of Campinas, Sao Paulo, Brazil. The research examines the fundamentals of confinement of the rare earth in the nanostructure. This is being evaluated in terms of: size dependence of the host crystalline Si, average Er 3+ concentration, local Er3+ coordination, and average Er3+ location for doped, soluble nanocrystals isolated from pyrolysis reactions. Centering on the high temperature pyrolysis of disilane (Si2H6 ) or silane (SiH4) and a rare earth precursor complex under carefully-controlled conditions, the resultant nanostructures are being characterized by photoluminescence (PL) spectroscopy, UV/visible optical absorption spectroscopy, transmission electron microscopy / high resolution electron microscopy (TEM/HREM), Raman spectroscopy, and Extended X-ray Absorption Fine Structure (EXAFS) measurements. EXAFS measurements performed at the Brazilian National Light Source are crucial to correlating local erbium structure with other structural features of the nanostructure, including its associated photophysical behavior. Site-specific control of any dopant atoms is a central and unanswered issue in the legitimate structural control of the next generation of nanoscale electronic materials. The international collaboration provides an interdisciplinary training experience to the junior scientists in materials chemistry at TCU, their counterparts in applied physics in Brazil, and permits the evolution of future research opportunities through networking for all involved. This award is supported by the Division of Materials Research, the Office of International Science and Engineering, and the Office of Multidisciplinary Activities in the Directorate for Mathematical and Physical Sciences.