Fabrication of ultra-sharp tips from carbon fiber for scanning tunneling microscopy investigations of epitaxial graphene on 6H-SiC(0001) surface

Abstract The fabrication of ultra-sharp tips from carbon fiber (CF), which are mounted on a qPlus probe for combined dynamic scanning tunneling microscopy (STM) and frequency modulation atomic force microscopy (FM-AFM) experiments, is reported. The carbon fiber tips were electrochemically etched in a KOH or NaOH solution, using different electronic devices. CF tips with an apex radius ∼10 nm, as deduced from the measured slopes of the Fowler–Nordheim plots (kR  ( 6 3 × 6 3 ) R30° reconstruction was regularly imaged by STM working either in non-oscillating mode or in dynamic mode, which also maps the variations of the force gradient. From these measurements with a constant mean-tunneling-current of 20 pA, it was found that the STM tip suffered variations of the tip/surface force gradient in between 8.25 and 16.50 N/m when it scanned the epitaxial graphene layer on the reconstructed 6H-SiC(0 0 0 1) surface.

[1]  G. Binnig,et al.  Scanning tunneling microscopy , 1984 .

[2]  H. B. Weber,et al.  Atomic and electronic structure of few-layer graphene on SiC(0001) studied with scanning tunneling microscopy and spectroscopy , 2008 .

[3]  William Paul,et al.  Refined tip preparation by electrochemical etching and ultrahigh vacuum treatment to obtain atomically sharp tips for scanning tunneling microscope and atomic force microscope. , 2011, The Review of scientific instruments.

[4]  Franz J. Giessibl,et al.  HIGH-SPEED FORCE SENSOR FOR FORCE MICROSCOPY AND PROFILOMETRY UTILIZING A QUARTZ TUNING FORK , 1998 .

[5]  A. Schulte,et al.  Easily made and handled carbon nanocones for scanning tunneling microscopy and electroanalysis , 2011 .

[6]  R. Gomer,et al.  Field Emission and Field Ionization , 1961 .

[7]  M. Radmacher,et al.  From molecules to cells: imaging soft samples with the atomic force microscope. , 1992, Science.

[8]  L. Libioulle,et al.  VERY SHARP PLATINUM TIPS FOR SCANNING TUNNELING MICROSCOPY , 1995 .

[9]  M. Fotino.  Tip sharpening by normal and reverse electrochemical etching , 1993 .

[10]  A. Kucernak,et al.  Fabrication of carbon microelectrodes with an effective radius of 1 nm , 2002 .

[11]  A. Lucier.  Preparation and Characterization of Tungsten Tips Suitable for Molecular Electronics Studies , 2004 .

[12]  M. Meyyappan,et al.  Carbon nanotube tip probes: stability and lateral resolution in scanning probe microscopy and application to surface science in semiconductors , 2001 .

[13]  N. Agraït,et al.  Carbon fibre tips for scanning probe microscopy based on quartz tuning fork force sensors , 2010, Nanotechnology.

[14]  C. Quate,et al.  Local spectroscopy and atomic imaging of tunneling current, forces, and dissipation on graphite. , 2005, Physical Review Letters.

[15]  Bing-Feng Ju,et al.  Systematic study of electropolishing technique for improving the quality and production reproducibility of tungsten STM probe , 2009 .

[16]  P. Mallet,et al.  Ripples in epitaxial graphene on the Si-terminated SiC(0001) surface , 2008 .

[17]  R. Chow,et al.  Cylindrically etched carbon-fiber microelectrodes for low-noise amperometric recording of cellular secretion. , 1998, Analytical chemistry.

[18]  J. Penuelas,et al.  Surface morphology and characterization of thin graphene films on SiC vicinal substrate , 2009 .

[19]  Rachid Belkhou,et al.  Large-area and high-quality epitaxial graphene on off-axis SiC wafers. , 2012, ACS nano.

[20]  K. Maeda,et al.  A reproducible method to fabricate atomically sharp tips for scanning tunneling microscopy , 1999 .

[21]  J. Polesel-Maris,et al.  Combined dynamic scanning tunneling microscopy and frequency modulation atomic force microscopy investigations on polythiophene chains on graphite with a tuning fork sensor , 2011 .

[22]  Revealing the atomic structure of the buffer layer between SiC(0001) and epitaxial graphene , 2011, 1111.4918.

[23]  Lionel Buchaillot,et al.  Investigation of the carbon nanotube AFM tip contacts: free sliding versus pinned contact , 2009, Nanotechnology.

[24]  B. P. Ng,et al.  Improve performance of scanning probe microscopy by balancing tuning fork prongs. , 2009, Ultramicroscopy.

[25]  L. Peng,et al.  Engineering the cap structure of individual carbon nanotubes and corresponding electron field emission characteristics , 2006 .

[26]  P. Grutter,et al.  Determination of the atomic structure of scanning probe microscopy tungsten tips by field ion microscopy , 2005 .

[27]  D. Edie.  The effect of processing on the structure and properties of carbon fibers , 1998 .

[28]  Robert D. Grober,et al.  Piezo-electric tuning fork tip—sample distance control for near field optical microscopes , 1995 .

[29]  K. Mørch,et al.  Preparation of platinum/iridium scanning probe microscopy tips , 1999 .

[30]  J. Gómez‐Herrero,et al.  WSXM: a software for scanning probe microscopy and a tool for nanotechnology. , 2007, The Review of scientific instruments.

[31]  C. Spindt,et al.  Physical properties of thin‐film field emission cathodes with molybdenum cones , 1976 .

[32]  N. Wilson,et al.  Carbon nanotube tips for atomic force microscopy. , 2009, Nature nanotechnology.

[33]  H. Morikawa,et al.  Reproducible sharp‐pointed tip preparation for field ion microscopy by controlled ac polishing , 1988 .

[34]  S. Torbruegge,et al.  Application of the KolibriSensor® to combined atomic-resolution scanning tunneling microscopy and noncontact atomic-force microscopy imaging , 2010 .

[35]  Richard J. Colton,et al.  On the electrochemical etching of tips for scanning tunneling microscopy , 1990 .

[36]  M. Armstrong‐James,et al.  A method for etching the tips of carbon fibre microelectrodes , 1980, Journal of Neuroscience Methods.

[37]  G. Schwitzgebel,et al.  AN IMPROVED LAMELLAE DROP-OFF TECHNIQUE FOR SHARP TIP PREPARATION IN SCANNING TUNNELING MICROSCOPY , 1997 .

[38]  Andres Castellanos-Gomez,et al.  Characterization and Optimization of Quartz Tuning Fork-Based Force Sensors for Combined STM/AFM , 2012 .

[39]  M. Shiraishi,et al.  Work function of carbon nanotubes , 2001 .

[40]  J. Cuevas,et al.  Carbon tips for all-carbon single-molecule electronics. , 2014, Nanoscale.

[41]  E. Müller.  Work Function of Tungsten Single Crystal Planes Measured by the Field Emission Microscope , 1955 .

[42]  R. Fowler,et al.  Electron Emission in Intense Electric Fields , 1928 .

[43]  G. Duvaut.  Mécanique des milieux continus , 1990 .

[44]  A. Melmed.  The art and science and other aspects of making sharp tips , 1991 .

[45]  Hal Edwards,et al.  Fast, high-resolution atomic force microscopy using a quartz tuning fork as actuator and sensor , 1997 .

[46]  U. Starke,et al.  Epitaxial graphene on SiC(0001) and : from surface reconstructions to carbon electronics , 2009, Journal of physics. Condensed matter : an Institute of Physics journal.

[47]  R. Birge,et al.  Ultrasharp and high aspect ratio carbon nanotube atomic force microscopy probes for enhanced surface potential imaging , 2008, Nanotechnology.

[48]  Carbon-fiber tips for scanning probe microscopes and molecular electronics experiments , 2012, Nanoscale Research Letters.

[49]  Franz J. Giessibl,et al.  Advances in atomic force microscopy , 2003, cond-mat/0305119.

[50]  T. Fujii,et al.  Micropattern measurement with an atomic force microscope , 1991 .

[51]  M. Mousa.  Electron emission from carbon fibre tips , 1996 .