title: Mapping of Defects in Individual Silicon Nanocrystals Using Real-Space Spectroscopy.
abstract: The photophysical properties of silicon semiconductor nanocrystals (SiNCs) are extremely sensitive to the presence of surface chemical defects, many of which are easily produced by oxidation under ambient conditions. The diversity of chemical structures of such defects and the lack of tools capable of probing individual defects continue to impede understanding of the roles of these defects in SiNC photophysics. We use scanning tunneling spectroscopy to study the impact of surface defects on the electronic structures of hydrogen-passivated SiNCs supported on the Au(111) surface. Spatial maps of the local electronic density of states (LDOS) produced by our measurements allowed us to identify locally enhanced defect-induced states as well as quantum-confined states delocalized throughout the SiNC volume. We use theoretical calculations to show that the LDOS spectra associated with the observed defects are attributable to Si-O-Si bridged oxygen or Si-OH surface defects.
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, United States.
authors.forename: Dmitry A
authors.initials: DA
authors.lastname: Kislitsyn
authors.affiliation: Department of Physics and Astronomy, Uppsala University , Box 516, SE-751 20 Uppsala, Sweden.
authors.forename: Vancho
authors.initials: V
authors.lastname: Kocevski
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, United States.
authors.forename: Jon M
authors.initials: JM
authors.lastname: Mills
authors.affiliation: Department of Chemistry, Portland State University , Portland, Oregon 97201, United States.
authors.forename: Sheng-Kuei
authors.initials: SK
authors.lastname: Chiu
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, United States.
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, United States.
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, United States.
authors.forename: Ariel E
authors.initials: AE
authors.lastname: Rosenfield
authors.affiliation: Department of Physics and Astronomy, Uppsala University , 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 , 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, United States.
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, United States.
authors.forename: George V
authors.initials: GV
authors.lastname: Nazin