Structure and Reactivity of Nano-Scale Holes in Single Sheet BN: Experiment and Theory

University Of Minnesota-Twin Cities, Minneapolis MN

Investigators

Abstract

NON-TECHNICAL DESCRIPTION: The goal of this research is to improve the understanding of the formation, stability, and chemical reactivity of the nano-size holes in single sheet boron nitride (BN) for use as a filter and biodetector; and to study the effects of those holes on the electrical and mechanical properties of the entire BN sheet. Using atomic-resolution electron microscopy, new insight into the atomic structure of the holes and defects in single-atom-thick BN sheets will be provided. The project will improve the understanding of the changes in current-conduction in these BN sheets in the presence of the holes and defects, allowing evaluation of their true potential for next generation electronics applications. This research will also be instrumental in determining the possibilities of using single BN sheets for filtration and biodetection applications. In addition to training graduate students, the education component includes improving and expanding the new courses on Electron Microscopy and Computational Nanomechanics, providing summer research opportunities for undergraduate students, and participating in outreach programs with local high school students. TECHNICAL DETAILS: A systematic study the formation, mechanical stability and chemical reactivity of the nano-scale holes in the single sheet h-BN will be undertaken by combining several experimental imaging and spectroscopy techniques in scanning transmission electron microscope (STEM) with theoretical predications based on calculations from first principles. Unlike conventional TEM imaging, the STEM probe electrons are scattered from the electrostatic potential of the atoms in the sample and recorded by a single-electron-sensitive annular dark field detector. This provides atomic-resolution images of the BN with direct and unambiguous atomic location identification. The spectroscopic analysis will be measured by electronic excitations inside single atoms of boron and nitrogen using electron energy loss spectroscopy (EELS). Theoretical predictions for the local density-of-states calculated for both atoms will be compared with EELS results; later, mechanical properties will be evaluated.