title: Vibrational spectroscopy in the electron microscope.
abstract: Vibrational spectroscopies using infrared radiation, Raman scattering, neutrons, low-energy electrons and inelastic electron tunnelling are powerful techniques that can analyse bonding arrangements, identify chemical compounds and probe many other important properties of materials. The spatial resolution of these spectroscopies is typically one micrometre or more, although it can reach a few tens of nanometres or even a few ångströms when enhanced by the presence of a sharp metallic tip. If vibrational spectroscopy could be combined with the spatial resolution and flexibility of the transmission electron microscope, it would open up the study of vibrational modes in many different types of nanostructures. Unfortunately, the energy resolution of electron energy loss spectroscopy performed in the electron microscope has until now been too poor to allow such a combination. Recent developments that have improved the attainable energy resolution of electron energy loss spectroscopy in a scanning transmission electron microscope to around ten millielectronvolts now allow vibrational spectroscopy to be carried out in the electron microscope. Here we describe the innovations responsible for the progress, and present examples of applications in inorganic and organic materials, including the detection of hydrogen. We also demonstrate that the vibrational signal has both high- and low-spatial-resolution components, that the first component can be used to map vibrational features at nanometre-level resolution, and that the second component can be used for analysis carried out with the beam positioned just outside the sample--that is, for 'aloof' spectroscopy that largely avoids radiation damage.
authors.affiliation: 1] Nion Company, 1102 Eighth Street, Kirkland, Washington 98033, USA [2] Department of Physics, Arizona State University, Tempe, Arizona 85287, USA.
authors.forename: Ondrej L
authors.initials: OL
authors.lastname: Krivanek
authors.affiliation: Nion Company, 1102 Eighth Street, Kirkland, Washington 98033, USA.
authors.forename: Tracy C
authors.initials: TC
authors.lastname: Lovejoy
authors.affiliation: Nion Company, 1102 Eighth Street, Kirkland, Washington 98033, USA.
authors.forename: Niklas
authors.initials: N
authors.lastname: Dellby
authors.affiliation: LeRoy Eyring Center for Solid State Science, Arizona State University, Tempe, Arizona 85287, USA.
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Aoki
authors.affiliation: Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287, USA.
authors.forename: R W
authors.initials: RW
authors.lastname: Carpenter
authors.affiliation: Department of Physics, Arizona State University, Tempe, Arizona 85287, USA.
authors.forename: Peter
authors.initials: P
authors.lastname: Rez
authors.affiliation: 1] LeRoy Eyring Center for Solid State Science, Arizona State University, Tempe, Arizona 85287, USA [2] Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287, USA.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Soignard
authors.affiliation: 1] LeRoy Eyring Center for Solid State Science, Arizona State University, Tempe, Arizona 85287, USA [2] TDK Headway Technologies Incorporated, Milpitas, California 95035, USA.
authors.forename: Jiangtao
authors.initials: J
authors.lastname: Zhu
authors.affiliation: 1] Institute for Advanced Materials, Devices and Nanotechnology, Rutgers University, Piscataway, New Jersey 08854, USA [2] Departments of Physics and Materials Science, Rutgers University, Piscataway, New Jersey 08854, USA.
authors.forename: Philip E
authors.initials: PE
authors.lastname: Batson
authors.affiliation: 1] Institute for Advanced Materials, Devices and Nanotechnology, Rutgers University, Piscataway, New Jersey 08854, USA [2] Departments of Physics and Materials Science, Rutgers University, Piscataway, New Jersey 08854, USA.
authors.forename: Maureen J
authors.initials: MJ
authors.lastname: Lagos
authors.affiliation: Department of Physics, University of Alberta, Edmonton T6G 2E1, Canada.
authors.forename: Ray F
authors.initials: RF
authors.lastname: Egerton
authors.affiliation: School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, Arizona 85287, USA.
authors.forename: Peter A
authors.initials: PA
authors.lastname: Crozier
mesh_terms: D004583:Electrons; D006859:Hydrogen / Q000032:analysis / Q000737:chemistry; D006860:Hydrogen Bonding; D017348:Microscopy, Electron, Scanning Transmission; D060739:Phonons; D013057:Spectrum Analysis / Q000379:methods*; D014732:Vibration
chemical_list: D006859:Hydrogen