Deconvolution of the density of states of tip and sample through constant-current tunneling spectroscopy

• Holger Pfeifer,
• Berndt Koslowski and
• Paul Ziemann

Beilstein J. Nanotechnol. 2011, 2, 607–617, doi:10.3762/bjnano.2.64

• developing a reliable deconvolution scheme shifts the focus towards how to access the actual transmission probability function. Keywords: deconvolution; Nb DOS; STM; STS; Introduction Undoubtedly, the power of scanning tunneling microscopy (STM) is based on its capability to map the surface topology of a

• conductive sample with resolution down to the atomic scale in real space [1]. Moreover, previous experience on metal–insulator–metal tunnel junctions [2] immediately suggested extending STM to become a local analytical tool, opening up the field of scanning tunneling spectroscopy (STS). The most prominent

• property that can be accessed by STS is the local electronic density of states (LDOS). For that purpose, the applied tunneling bias, V, is ramped while the probe–sample separation is kept constant (commonly denoted as I–V spectroscopy) [1][3]. However, determination of the sample LDOS from such a

Terthiophene on Au(111): A scanning tunneling microscopy and spectroscopy study

• Berndt Koslowski,
• Anna Tschetschetkin,
• Norbert Maurer,
• Elena Mena-Osteritz,
• Peter Bäuerle and
• Paul Ziemann

Beilstein J. Nanotechnol. 2011, 2, 561–568, doi:10.3762/bjnano.2.60

• Abstract Terthiophene (3T) molecules adsorbed on herringbone (HB) reconstructed Au(111) surfaces in the low coverage regime were investigated by means of low-temperature scanning tunneling microscopy (STM) and spectroscopy (STS) under ultra-high vacuum conditions. The 3T molecules adsorb preferentially in

• -separation (I-V) and constant-current (z-V) STS clearly reveal the highest occupied (HOMO) and lowest unoccupied (LUMO) molecular orbitals, which are found at −1.2 eV and +2.3 eV, respectively. The HOMO–LUMO gap corresponds to that of a free molecule, indicating a rather weak interaction between 3T and Au

• indicating an adsorption-induced dimensionality transition of the involved tunneling processes. Keywords: Au(111); electronic density of states; STM; STS; terthiophene; Introduction Because of their expedient properties and their diversity, oligo- and polythiophenes are among the most investigated organic

Organic–inorganic nanosystems

• Paul Ziemann

Beilstein J. Nanotechnol. 2011, 2, 363–364, doi:10.3762/bjnano.2.41

• (STS), while for larger coverages standard photoelectron spectroscopies such UPS or XPS – often synchrotron based – also play an important role. This broad spectrum of preparational approaches, analytical tools and sought after functionalities, all related to organic–inorganic nanosystems, are

Formation of precise 2D Au particle arrays via thermally induced dewetting on pre-patterned substrates

• Dong Wang,
• Ran Ji and
• Peter Schaaf

Beilstein J. Nanotechnol. 2011, 2, 318–326, doi:10.3762/bjnano.2.37

• square array of pyramidal pits (substrate type A), shown in Figure 1a, and an array of circular holes with square symmetry (substrate type B), shown in Figure 1b, by employing the substrate conformal imprint lithography (SCIL) and reactive ion etching (RIE, Oxford Plasmalab 100 and STS 320 PC). The SCIL

Defects in oxide surfaces studied by atomic force and scanning tunneling microscopy

• Thomas König,
• Georg H. Simon,
• Lars Heinke,
• Leonid Lichtenstein and
• Markus Heyde

Beilstein J. Nanotechnol. 2011, 2, 1–14, doi:10.3762/bjnano.2.1

• tunneling spectroscopy (STS). On magnesium oxide, different color centers, i.e., F0, F+, F2+ and divacancies, have different effects on the contact potential. These differences enabled classification and unambiguous differentiation by KPFM. True atomic resolution shows the topography at line defects in

• aluminum oxide. At these domain boundaries, STS and KPFM verify F2+-like centers, which have been predicted by density functional theory calculations. Thus, by determining the contact potential and the electronic structure with a spatial resolution in the nanometer range, NC-AFM and STM can be successfully

• defects. Here, we confine ourselves to different point defects in magnesium oxide and to line defects in aluminum oxide. Both samples were prepared as thin films on metal supports. As a consequence, STM and scanning tunneling spectroscopy (STS) can be performed and conclusions about the electronic