title: Communication: Visualization and spectroscopy of defects induced by dehydrogenation in individual silicon nanocrystals.
abstract: We present results of a scanning tunneling spectroscopy (STS) study of the impact of dehydrogenation on the electronic structures of hydrogen-passivated silicon nanocrystals (SiNCs) supported on the Au(111) surface. Gradual dehydrogenation is achieved by injecting high-energy electrons into individual SiNCs, which results, initially, in reduction of the electronic bandgap, and eventually produces midgap electronic states. We use theoretical calculations to show that the STS spectra of midgap states are consistent with the presence of silicon dangling bonds, which are found in different charge states. Our calculations also suggest that the observed initial reduction of the electronic bandgap is attributable to the SiNC surface reconstruction induced by conversion of surface dihydrides to monohydrides due to hydrogen desorption. Our results thus provide the first visualization of the SiNC electronic structure evolution induced by dehydrogenation and provide direct evidence for the existence of diverse dangling bond states on the SiNC surfaces.
authors.affiliation: Department of Chemistry and Biochemistry, Materials Science Institute, Oregon Center for Optical, Molecular and Quantum Science, University of Oregon, 1253 University of Oregon, Eugene, Oregon 97403, USA.
authors.forename: Dmitry A
authors.initials: DA
authors.lastname: Kislitsyn
authors.affiliation: Department of Chemistry and Biochemistry, Materials Science Institute, Oregon Center for Optical, Molecular and Quantum Science, University of Oregon, 1253 University of Oregon, Eugene, Oregon 97403, USA.
authors.forename: Jon M
authors.initials: JM
authors.lastname: Mills
authors.affiliation: Department of Physics and Astronomy, Uppsala University, P.O. Box 516, SE-751 20 Uppsala, Sweden.
authors.forename: Vancho
authors.initials: V
authors.lastname: Kocevski
authors.affiliation: Department of Chemistry, Portland State University, Portland, Oregon 97201, USA.
authors.forename: Sheng-Kuei
authors.initials: SK
authors.lastname: Chiu
authors.affiliation: Department of Chemistry, Portland State University, Portland, Oregon 97201, USA.
authors.forename: William J I
authors.initials: WJ
authors.lastname: DeBenedetti
authors.affiliation: Department of Chemistry and Biochemistry, Materials Science Institute, Oregon Center for Optical, Molecular and Quantum Science, University of Oregon, 1253 University of Oregon, Eugene, Oregon 97403, USA.
authors.forename: Christian F
authors.initials: CF
authors.lastname: Gervasi
authors.affiliation: Department of Chemistry and Biochemistry, Materials Science Institute, Oregon Center for Optical, Molecular and Quantum Science, University of Oregon, 1253 University of Oregon, Eugene, Oregon 97403, USA.
authors.forename: Benjamen N
authors.initials: BN
authors.lastname: Taber
authors.affiliation: Department of Chemistry and Biochemistry, Materials Science Institute, Oregon Center for Optical, Molecular and Quantum Science, University of Oregon, 1253 University of Oregon, Eugene, Oregon 97403, USA.
authors.forename: Ariel E
authors.initials: AE
authors.lastname: Rosenfield
authors.affiliation: Department of Physics and Astronomy, Uppsala University, P.O. Box 516, SE-751 20 Uppsala, Sweden.
authors.forename: Olle
authors.initials: O
authors.lastname: Eriksson
authors.affiliation: Department of Physics and Astronomy, Uppsala University, P.O. Box 516, SE-751 20 Uppsala, Sweden.
authors.forename: Ján
authors.initials: J
authors.lastname: Rusz
authors.affiliation: Department of Chemistry, Portland State University, Portland, Oregon 97201, USA.
authors.forename: Andrea M
authors.initials: AM
authors.lastname: Goforth
authors.affiliation: Department of Chemistry and Biochemistry, Materials Science Institute, Oregon Center for Optical, Molecular and Quantum Science, University of Oregon, 1253 University of Oregon, Eugene, Oregon 97403, USA.
authors.forename: George V
authors.initials: GV
authors.lastname: Nazin