In situ growth optimization in focused electron-beam induced deposition

• Paul M. Weirich,
• Marcel Winhold,
• Christian H. Schwalb and
• Michael Huth

Beilstein J. Nanotechnol. 2013, 4, 919–926, doi:10.3762/bjnano.4.103

• changing the deposition parameters. Here, we present a first implementation of such a feedback control mechanism and employ an evolutionary genetic algorithm (GA) for the in situ optimization of the electrical conductivity of nanostructures that are prepared by FEBID [17]. By using the time gradient of the

• measured in situ conductance as a fitness parameter for the GA we are able to tune the properties of the deposits towards highest conductivity. In order to demonstrate the efficiency of this method, we chose W(CO)6. Our study reveals that an increase of conductivity by one order of magnitude can be

• achieved with the GA by solely varying the process parameters pitch p and dwell-time tD in the deposition process. The precursor-specific limitations of the approach are also exemplified for another precursor, MeCpPt(Me)3, which is known to show only one bond-cleavage in the initial step [18]. This results

Challenges in realizing ultraflat materials surfaces

• Takashi Yatsui,
• Wataru Nomura,
• Fabrice Stehlin,
• Olivier Soppera,
• Makoto Naruse and
• Motoichi Ohtsu

Beilstein J. Nanotechnol. 2013, 4, 875–885, doi:10.3762/bjnano.4.99

• of 0.140 nm obtained for GaN might be limited by the value of the interatomic distance between Ga and N of 0.195 nm for hexagonal GaN [40]. Furthermore, R(l) again shows the individual contributions of the surface roughness at different length scales to the overall surface roughness, as shown in

Synthesis of indium oxi-sulfide films by atomic layer deposition: The essential role of plasma enhancement

• Cathy Bugot,
• Nathanaëlle Schneider,
• Daniel Lincot and
• Frédérique Donsanti

Beilstein J. Nanotechnol. 2013, 4, 750–757, doi:10.3762/bjnano.4.85

• tuned. Keywords: atomic layer deposition; buffer layer; indium oxi-sulfide; plasma enhancement; thin film solar cells; Introduction Chalcopyrite-type thin film solar cells that are based on a Cu(In,Ga)Se2 (CIGS) absorber have reached high efficiencies, up to 20.3% [1] in 2011 and 20.4% [2] on flexible

• during the O2 plasma pulses. Due to the reactivity of the plasma, the film surfaces cannot be considered as a static system but should rather be seen as continually re-structured surfaces. In our future studies, those films will be applied as buffer layer in Cu(In,Ga)Se2 solar cells to investigate their

Evolution of microstructure and related optical properties of ZnO grown by atomic layer deposition

• Adib Abou Chaaya,
• Roman Viter,
• Mikhael Bechelany,
• Zanda Alute,
• Donats Erts,
• Anastasiya Zalesskaya,
• Kristaps Kovalevskis,
• Vincent Rouessac,
• Valentyn Smyntyna and
• Philippe Miele

Beilstein J. Nanotechnol. 2013, 4, 690–698, doi:10.3762/bjnano.4.78

• Information Supporting Information File 38: Additional figures. Acknowledgements The study was partially supported by the EU grant under BIOSENSORS-AGRICULT, Contract PIRSES-GA-2012-318520 “DEVELOPMENT OF NANOTECHNOLOGY BASED BIOSENSORS FOR AGRICULTURE”. The authors are thankful to Dr. Janis Abolins for

A nano-graphite cold cathode for an energy-efficient cathodoluminescent light source

• Alexander N. Obraztsov,
• Victor I. Kleshch and
• Elena A. Smolnikova

Beilstein J. Nanotechnol. 2013, 4, 493–500, doi:10.3762/bjnano.4.58

• (Grant PIRSES-GA-2011-295241).

Structural and thermoelectric properties of TMGa₃ (TM = Fe, Co) thin films

• Sebastian Schnurr,
• Ulf Wiedwald,
• Paul Ziemann,
• Valeriy Y. Verchenko and
• Andrei V. Shevelkov

Beilstein J. Nanotechnol. 2013, 4, 461–466, doi:10.3762/bjnano.4.54

• 43 nm. Backscattering energies of Co, Ga and Si at the sample surface are indicated by vertical marks. The displacement of the Si edge of the substrate toward lower backscattering energies is caused by the film thickness. Electrical resistivity of FeGa3, CoGa3 and Fe0.75Co0.25Ga3 films as a function

Magnetic anisotropy of graphene quantum dots decorated with a ruthenium adatom

• Igor Beljakov,
• Velimir Meded,
• Franz Symalla,
• Karin Fink,
• Sam Shallcross and
• Wolfgang Wenzel

Beilstein J. Nanotechnol. 2013, 4, 441–445, doi:10.3762/bjnano.4.51

• 100 Å away from the flake plane. Acknowledgements We acknowledge financial support from EC FP7 e-infrastructures project MMM@HPC (GA 261594). KF thanks for support by the DFG-funded Transregional Collaborative Research Center SFB/TRR 88 “3 MET”. SS acknowledges the financial support of the

Synthesis and electrical characterization of intrinsic and in situ doped Si nanowires using a novel precursor

• Wolfgang Molnar,
• Alois Lugstein,
• Tomasz Wojcik,
• Peter Pongratz,
• Norbert Auner,
• Christian Bauch and
• Emmerich Bertagnolli

Beilstein J. Nanotechnol. 2012, 3, 564–569, doi:10.3762/bjnano.3.65

• adding HCl to the growth atmosphere [18]. For such VLS grown NW dopants can be introduced either through particular catalyst particles, such as In [19], Al [20] or Ga [21], which become partly incorporated into the NW during growth and thus work as p-type dopants themselves, or by adding a small amount

FTIR nanobiosensors for Escherichia coli detection

• Stefania Mura,
• Gianfranco Greppi,
• Maria Laura Marongiu,
• Pier Paolo Roggero,
• Sandeep P. Ravindranath,
• Lisa J. Mauer,
• Nicoletta Schibeci,
• Francesco Perria,
• Massimo Piccinini,
• Plinio Innocenzi and
• Joseph Irudayaraj

Beilstein J. Nanotechnol. 2012, 3, 485–492, doi:10.3762/bjnano.3.55

• necessary to improve the safety of our food supply chain. In this work we report on mesoporous titania thin-film substrates as sensors to detect E. coli O157:H7. Titania films treated with APTES ((3-aminopropyl)triethoxysilane) and GA (glutaraldehyde) were functionalized with specific antibodies and the

• %), glutaraldehyde (GA Grade I, 50% in H2O, specially purified for use as an electron microscopy fixative or other sophisticated use) were purchased from Sigma Aldrich (Germany). E. coli O157:H7 and E. coli K12 were obtained from the bacteria collection at Purdue University (Agricultural and Biological Engineering

• dried in air. The following functionalization of TiO2–APTES films with GA was obtained by immersing the films in GA 50% (v/v) in water for 24 h, washing with water and EtOH and drying at room temperature. Different experiments were realized, providing the immobilization of antibodies directly on titania

Junction formation of Cu₃BiS₃ investigated by Kelvin probe force microscopy and surface photovoltage measurements

• Fredy Mesa,
• William Chamorro,
• William Vallejo,
• Robert Baier,
• Thomas Dittrich,
• Alexander Grimm,
• Martha C. Lux-Steiner and
• Sascha Sadewasser

Beilstein J. Nanotechnol. 2012, 3, 277–284, doi:10.3762/bjnano.3.31

• charge-selective contact has to be increased. Keywords: buffer layer; Cu3BiS3; Kelvin probe force microscopy; solar cells; Introduction Thin-film solar cells based on absorbers made from Cu(In,Ga)Se2 [1] or CdTe [2] reach the highest efficiencies currently available. Both semiconductors are interesting

• photovoltaic active interface with a SPV of ~130 mV [7]. It is well known from the Cu(In,Ga)Se2 solar cells that a buffer layer is required between the n-ZnO window and the p-type absorber layer to reach high efficiency values [8]. Traditionally, CdS deposited by chemical bath deposition (CBD) has been used as

• , such as chemical bath deposition, atomic layer deposition, ion layer gas reaction (ILGAR) deposition, evaporation, and spray deposition [9]. One interesting aspect of the above mentioned solar cell materials CdTe and Cu(In,Ga)Se2 is their high efficiency despite the abundance of grain boundaries (GBs

Current-induced forces in mesoscopic systems: A scattering-matrix approach

• Niels Bode,
• Silvia Viola Kusminskiy,
• Reinhold Egger and
• Felix von Oppen

Beilstein J. Nanotechnol. 2012, 3, 144–162, doi:10.3762/bjnano.3.15

• order in , with G< = GR∑<GA. Current-induced forces in terms of Green’s functions We can now collect the results from the previous section and identify the current-induced forces appearing in the Langevin Equation 1. Except for the stochastic noise force, the current-induced forces are encoded in . In

• explicitly and using Equation 88 in Supporting Information File 1, Section A, we can express G< in terms of GR and GA and obtain where the second equality exploits the cyclic invariance of the trace. Noting that, by Equation 93 in Supporting Information File 1, Section A, Equation 37 can be expressed

When “small” terms matter: Coupled interference features in the transport properties of cross-conjugated molecules

• Gemma C. Solomon,
• Justin P. Bergfield,
• Charles A. Stafford and
• Mark A. Ratner

Beilstein J. Nanotechnol. 2011, 2, 862–871, doi:10.3762/bjnano.2.95

• transmission is generally calculated as [21] Gr(E) is the retarded Green’s function of the junction at energy E, Ga(E) is its conjugate transpose, and ΓL and ΓR are the broadening matrices describing the coupling to the left and right electrodes, respectively. In each of the three theoretical methods discussed

Dense lying self-organized GaAsSb quantum dots on GaAs for efficient lasers

• Thomas H. Loeber,
• Dirk Hoffmann and
• Henning Fouckhardt

Beilstein J. Nanotechnol. 2011, 2, 333–338, doi:10.3762/bjnano.2.39

• –Krastanov (SK) epitaxial mode. Their characteristics were dependent on the Sb/Ga (V/III) flux ratio and the growth temperature. The samples were grown with a V/III ratio between 0.45/1 and 1.50/1 and a temperature between 445 and 580 °C, not commonly used by other research groups. These parameters enabled

• (SK) growth, depending on the precise control of the Sb/Ga V/III flux ratio, coverage, and growth temperature. Furthermore these parameters influence dot shape, size and density. The staggered (type-II) band alignment with a large valence band offset provides hole confinement. The electronic states

• lie in the GaAs conduction band continuum [1][2]. Bimberg et al. grew GaSb on GaAs with variable GaSb layer thickness [2][3][4][5]. Huffaker et al. achieved QDs by variation of the Sb/Ga flux ratio (V/III ratio) between 1.00/1 and 6.50/1 with a maximum dot density around 2.9 × 1010 cm−2 [1][6][7][8][9

On the reticular construction concept of covalent organic frameworks

• Binit Lukose,
• Agnieszka Kuc,
• Johannes Frenzel and
• Thomas Heine

Beilstein J. Nanotechnol. 2010, 1, 60–70, doi:10.3762/bjnano.1.8

• calculated COF parameters. Supporting Information File 4: CIFs for selected structures. Acknowledgements Financial support by the European Union through the collaborative project FP7-NMP-2008-EU-India-2 GA 233482 and the German Research Council (DFG) is gratefully acknowledged.