A hybrid scanning tunneling/optical near-field microscope is presented, in which an optical fiber tip coated with 100 nm thick Ag/Cr films scans the surface. The tip metallization enables operating the instrument via a current-based distance control and guarantees sub-nanometer spatial resolution in the topographic channel. The fiber tip simultaneously serves as nanoscale light source, given the optical transparency of the metal coating. The emission response of the tip–sample junction is collected with two parabolic mirrors and probed with a far-field detector. To test the capabilities of the new setup, the evolution of the optical signal is monitored when the tip approaches a gold surface. The intensity rise and frequency shift of the emission provide evidence for the development of coupled plasmon modes in the tip–sample cavity. Photon mapping is employed to probe the optical inhomogeneity of Ru(0001) and TiO2(110) surfaces covered with silver deposits. While the 2D Ag flakes on Ru give rise to a near-field enhancement, the 3D particles on titania locally damp the gap plasmons and lower the emitted intensity. The lateral resolution in the optical channel has been estimated to be ∼1 nm, and optical and topographic signals are well correlated. Our fiber microscope thus appears to be suitable for probing optical surface properties at the nanoscale.
REFERENCES
1.
L.
Novotny
and B.
Hecht
, Principles of Nano-Optics
(Cambridge University Press
, 2006
).2.
J. H.
Kim
and K. B.
Song
, “Recent progress of nano-technology with NSOM
,” Micron
38
, 409
(2007
).3.
J. M.
Atkin
, S.
Berweger
, A. C.
Jones
, and M. B.
Raschke
, “Nano-optical imaging and spectroscopy of order, phases and domains in complex solids
,” Adv. Phys.
61
, 745
–842
(2012
).4.
U.
Kreibig
and W.
Vollmer
, Optical Properties of Metal Clusters
, Springer Series Vol. 25 (Springer
, 1995
).5.
N. J.
Halas
, S.
Lal
, W. S.
Chang
, S.
Link
, and P.
Nordlander
, “Plasmons in strongly coupled metallic nanostructures
,” Chem. Rev.
111
, 3913
–3961
(2011
).6.
J.
Olson
, S.
Dominguez-Medina
, A.
Hoggard
, L.-Y.
Wang
, W.-S.
Chang
, and S.
Link
, “Optical characterization of single plasmonic nanoparticles
,” Chem. Soc. Rev.
44
, 40
–57
(2015
).7.
B.
Henderson
and G. F.
Imbusch
, Optical Spectroscopy of Inorganic Solids
(Clarendon Press
, Oxford
, 1989
);S.
Hüfner
, Optical Spectra of Transparent Rare Earth Compounds
(Academic Press
, New York
, 1978
).8.
A.
Janotti
and C.
van de Walle
, “Fundamentals of zinc oxide as a semiconductor
,” Rep. Prog. Phys.
72
, 126501
(2009
).9.
N.
Nilius
, “Exploring routes to tailor the physical and chemical properties of oxides via doping: An STM study
,” J. Phys.: Condens. Matter
27
, 303001
(2015
).10.
A.
Ishizumi
, K.
Matsuda
, T.
Saiki
, C. W.
White
, and Y.
Kanemitsu
, “Photoluminescence properties of single Mn-doped CdS nanocrystals studied by scanning near-field optical microscopy
,” Appl. Phys. Lett.
87
, 133104
(2005
).11.
R. C.
Somers
, M.
Bawendi
, G.
Moungi
, and D. G.
Nocera
, “CdSe nanocrystal based chem-/bio-sensors
,” Chem. Soc. Rev.
36
, 579
–591
(2007
).12.
E.
Hilner
, U.
Hakanson
, P.
Kratzer
, E.
Lundgren
, L.
Samuelson
, and A.
Mikkelsen
, “Direct atomic scale imaging of III−V nanowire surfaces
,” Nano Lett.
8
, 3978
–3982
(2008
).13.
X. H.
Qiu
, G. V.
Nazin
, and W.
Ho
, “Vibrationally resolved fluorescence excited with submolecular precision
,” Science
299
, 542
–546
(2003
).14.
F.
Kulzer
and M.
Orrit
, “Single-molecule optics
,” Annu. Rev. Phys. Chem.
55
, 585
–611
(2004
).15.
S.
Sahl
, S. W.
Hell
, and S.
Jakobs
, “Fluorescence nanoscopy in cell biology
,” Nat. Rev. Mol. Cell Biol.
18
, 685
–701
(2017
).16.
L.
Novotny
and S. J.
Stranick
, “Near-field optical microscopy and spectroscopy with pointed probes
,” Annu. Rev. Phys. Chem.
57
, 303
–331
(2006
);
[PubMed]
A.
Hartschuh
, “Tip-enhanced near-field optical microscopy
,” Angew. Chem., Int. Ed.
47
, 8178
–8191
(2008
).17.
C.
Ropers
, C. C.
Neacsu
, T.
Elsaesser
, M.
Albrecht
, M. B.
Raschke
, and C.
Lienau
, “Grating-coupling of surface plasmons onto metallic tips: A nanoconfined light source
,” Nano Lett.
7
, 2784
–2788
(2007
).18.
S.
Schmidt
, B.
Piglosiewicz
, J.
Shirdel
, J. S.
Lee
, P.
Vasa
, N.
Park
, D. S.
Kim
, and C.
Lienau
, “Adiabatic nanofocusing on ultrasmooth single-crystalline gold tapers creates a 10-nm-sized light source with few-cycle time resolution
,” ACS Nano
6
, 6040
–6048
(2012
).19.
R.
Berndt
, J. K.
Gimzewski
, and P.
Johansson
, “Inelastic tunneling excitation of tip-induced plasmon modes on noble-metal surfaces
,” Phys. Rev. Lett.
67
, 3796
(1991
).20.
F.
Rossel
, M.
Pivetta
, and W.-D.
Schneider
, “Luminescence experiments on supported molecules with the scanning tunneling microscope
,” Surf. Sci. Rep.
65
, 129
–144
(2010
).21.
A.
Downes
and M. E.
Welland
, “Photon emission from Si(111)-(7 × 7) induced by scanning tunneling microscopy: Atomic scale and material contrast
,” Phys. Rev. Lett.
81
, 1857
(1998
).22.
N.
Nilius
, N.
Ernst
, and H.-J.
Freund
, “Photon emission spectroscopy of individual oxide-supported silver clusters in a scanning tunneling microscope
,” Phys. Rev. Lett.
84
, 3994
(2000
).23.
G.
Hoffmann
, J.
Kliewer
, and R.
Berndt
, “Luminescence from metallic quantum wells in a scanning tunneling microscope
,” Phys. Rev. Lett.
87
, 176803
(2001
).24.
G.
Schull
, M.
Becker
, and R.
Berndt
, “Imaging confined electrons with plasmonic light
,” Phys. Rev. Lett.
101
, 136801
(2008
).25.
E.
Ćavar
, M. C.
Blüm
, M.
Pivetta
, F.
Patthey
, M.
Chergui
, and W. D.
Schneider
, “Fluorescence and phosphorescence from individual C60 molecules excited by local electron tunneling
,” Phys. Rev. Lett.
95
, 196102
(2005
).26.
N.
Krane
, C.
Lotze
, J. M.
Läger
, G.
Reecht
, and K. J.
Franke
, “Electronic structure and luminescence of quasi-freestanding MoS2 nanopatches on Au(111)
,” Nano Lett.
16
, 5163
(2016
).27.
Y. J.
Zheng
, Y.
Chen
, Y. L.
Huang
, P. K.
Gogoi
, M.-Y.
Li
, L.-J.
Li
, P. E.
Trevisanutto
, Q.
Wang
, S. J.
Pennycook
, A. T. S.
Wee
, and S. Y.
Quek
, “Point defects and localized excitons in 2D WSe2
,” ACS Nano
13
, 6050
–6059
(2019
).28.
P.
Johansson
, “Light emission from a scanning tunneling microscope: Fully retarded calculation
,” Phys. Rev. B
58
, 10823
(1998
).29.
T. L.
Cocker
, D.
Peller
, P.
Yu
, J.
Repp
, and R.
Huber
, “Tracking the ultrafast motion of a single molecule by femtosecond orbital imaging
,” Nature
539
, 263
–267
(2016
).30.
P.
Tománek
, J.
Brüstlová
, P.
Dobis
, and L.
Grmela
, “Hybrid STM/R-SNOM with novel probe
,” Ultramicroscopy
71
, 199
–203
(1998
).31.
J.
Steidtner
and B.
Pettinger
, “Tip-enhanced Raman spectroscopy and microscopy on single dye molecules with 15 nm resolution
,” Phys. Rev. Lett.
100
, 236101
(2008
).32.
S.
Jiang
, Y.
Zhang
, R.
Zhang
, M.
Liao
, Y.
Luo
, J.
Yang
, Z.
Dong
, and J. G.
Hou
, “Distinguishing adjacent molecules on a surface using plasmon-enhanced Raman scattering
,” Nat. Nanotechnol.
10
, 865
(2015
).33.
B.
Doppagne
, M. C.
Chong
, E.
Lorchat
, S.
Berciaud
, M.
Romeo
, H.
Bulou
, A.
Boeglin
, F.
Scheurer
, and G.
Schull
, “Vibronic spectroscopy with submolecular resolution from STM-induced electroluminescence
,” Phys. Rev. Lett.
118
, 127401
(2017
).34.
K.
Nakajima
, R.
Micheletto
, K.
Mitsui
, T.
Isoshima
, M.
Hara
, T.
Wada
, H.
Sasabe
, and W.
Knoll
, “Nanoscopic studies investigated by hybrid SNOM/STM
,” Appl. Surf. Sci.
144-145
, 520
–524
(1999
).35.
J.
Heimel
, U. C.
Fischer
, and H.
Fuchs
, “SNOM/STM using a tetrahedral tip and a sensitive current-to-voltage converter
,” J. Microsc.
202
, 53
–59
(2001
).36.
R. A. J.
Woolley
, J. A.
Hayton
, S.
Cavill
, J.
Ma
, P. H.
Beton
, and P.
Moriarty
, “A compact combined ultrahigh vacuum scanning tunneling microscope and near-field optical microscope
,” Meas. Sci. Technol.
19
, 045301
(2008
).37.
J.
Frohn
, J. F.
Wolf
, K.
Besocke
, and M.
Teske
, “An ultrahigh vacuum STM for use at variable temperature
,” Rev. Sci. Instrum.
60
, 1200
(1989
).38.
H.-J.
Freund
, N.
Nilius
, T.
Risse
, S.
Schauermann
, and T.
Schmidt
, “New measurement techniques in surface science
,” ChemPhysChem
12
, 79
(2011
).39.
B. N.
Persson
and A.
Baratoff
, “Theory of photon emission in electron tunneling to metallic particles
,” Phys. Rev. Lett.
68
, 3224
(1992
).40.
P.
Johansson
, R.
Monreal
, and P.
Apell
, “Theory for light emission from a scanning tunneling microscope
,” Phys. Rev. B
42
, 9210
(1990
).41.
S.
Wu
and D. L.
Mills
, “STM-induced enhancement of dynamic dipole moments on crystal surfaces: Theory of the lateral resolution
,” Phys. Rev. B
65
, 205420
(2002
).42.
K.
Luo
, T. P.
St. Clair
, X.
Lai
, and D. W.
Goodman
, “Silver growth on TiO2(110) (1 × 1) and (1 × 2)
,” J. Phys. Chem. B
104
, 3050
(2000
).43.
P.
Johansson
and R.
Monreal
, “Theory for photon emission from a scanning tunneling microscope
,” Z. Phys. B
84
, 269
(1991
).44.
W.
Rechberger
, A.
Hohenau
, A.
Leitner
, J. R.
Krenn
, B.
Lamprecht
, and F. R.
Aussenegg
, “Optical properties of two interacting gold nanoparticles
,” Opt. Commun.
220
, 137
–141
(2003
).45.
P. K.
Jain
, W.
Huang
, and M. A.
El-Sayed
, “On the universal scaling behavior of the distance decay of plasmon coupling in metal nanoparticle pairs
,” Nano Lett.
7
, 2080
–2088
(2007
).46.
B.
Pettinger
, K. F.
Domke
, D.
Zhang
, R.
Schuster
, and G.
Ertl
, “Direct monitoring of plasmon resonances in a tip-surface gap of varying width
,” Phys. Rev. B
76
, 113409
(2007
).47.
W. L.
Ling
, J. C.
Hamilton
, K.
Thürmer
, G. E.
Thayer
, J.
de la Figuera
, R. Q.
Hwang
, C. B.
Carter
, N. C.
Bartelt
, and K. F.
McCarty
, Surf. Sci.
600
, 1735
(2006
).48.
H.
Hövel
, S.
Fritz
, A.
Hilger
, U.
Kreibig
, and M.
Vollmer
, “Width of cluster plasmon resonances: Bulk dielectric functions and chemical interface damping
,” Phys. Rev. B
48
, 18178
(1993
).49.
L.
Pascua
, F.
Stavale
, N.
Nilius
, and H.-J.
Freund
, “Ag/ZnO hybrid systems studied with scanning tunneling microscopy-based luminescence spectroscopy
,” J. Appl. Phys.
119
, 095310
(2016
).© 2020 Author(s).
2020
Author(s)
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