May the force be with you - p271

doi:10.1038/nnano.2009.95

It may be thought that force is the province of physicists and structural engineers, but it is also important in many other areas of research.

Full Text - May the force be with you | PDF (84 KB) - May the force be with you

Subject Categories: Structural properties | Synthesis and processing

Mind the gap revisited - pp273 - 274

Alfred Nordmann & Arie Rip

doi:10.1038/nnano.2009.26

It is important to consider the ethical aspects of nanotechnology, but it is equally important to ensure that these considerations do not end up as 'speculative ethics'.

Full Text - Mind the gap revisited | PDF (104 KB) - Mind the gap revisited

Subject Category: Ethical, legal and other societal issues

Small differences - p275

Chris Toumey

doi:10.1038/nnano.2009.97

Nanomedicine and homeopathy both involve very small amounts of material, but that is where the similarity ends, as Chris Toumey explains.

Full Text - Small differences | PDF (86 KB) - Small differences

Subject Category: Nanomedicine

Our choice from the recent literature - pp276 - 277

doi:10.1038/nnano.2009.98

Full Text - Our choice from the recent literature | PDF (178 KB) - Our choice from the recent literature

Top down bottom up: Magnetic attraction - p277

doi:10.1038/nnano.2009.99

Full Text - Top down bottom up: Magnetic attraction | PDF (101 KB) - Top down bottom up: Magnetic attraction

Subject Category: Nanobiotechnology

Nanoelectronics: Oxides offer the write stuff - pp279 - 280

Dave H. A. Blank & Guus Rijnders

doi:10.1038/nnano.2009.103

An atomic force microscope has been used to create nanoscale field-effect transistors and other electronic devices at the interface between two different oxide materials.

Full Text - NanoelectronicsOxides offer the write stuff | PDF (253 KB) - NanoelectronicsOxides offer the write stuff

Subject Categories: Electronic properties and devices | Nanomaterials

Nanopatterning: What diffraction limit? - p280

Peter Rodgers

doi:10.1038/nnano.2009.94

Full Text - NanopatterningWhat diffraction limit? | PDF (133 KB) - NanopatterningWhat diffraction limit?

Subject Category: Surface patterning and imaging

DNA nanotechnology: A nanomachine goes live - pp281 - 282

Yuji Ishitsuka & Taekjip Ha

doi:10.1038/nnano.2009.101

A DNA-based device can act as a pH sensor inside living cells.

Full Text - DNA nanotechnologyA nanomachine goes live | PDF (189 KB) - DNA nanotechnologyA nanomachine goes live

Subject Categories: Molecular machines and motors | Nanosensors and other devices

Nanowires: Keeping track of dopants - pp282 - 283

Pavle V. Radovanovic

doi:10.1038/nnano.2009.104

Semiconductor nanowires need to be doped before they can be used for many applications, but this process is not well understood. A laser-based approach has now shed new light on the doping of nanowires.

Full Text - NanowiresKeeping track of dopants | PDF (189 KB) - NanowiresKeeping track of dopants

Subject Category: Nanomaterials

Graphene production: From nanotubes to nanoribbons - p283

Owain Vaughan

doi:10.1038/nnano.2009.96

Full Text - Graphene productionFrom nanotubes to nanoribbons | PDF (162 KB) - Graphene productionFrom nanotubes to nanoribbons

Subject Categories: Carbon nanotubes and fullerenes | Synthesis and processing

Mechanochemistry: Force probes in a bottle - pp284 - 285

Jeremy M. Lenhardt & Stephen L. Craig

doi:10.1038/nnano.2009.100

A rigid molecule that changes shape when exposed to light can be used to explore the influence of mechanical force on chemical reactions involving small functional groups.

Full Text - MechanochemistryForce probes in a bottle | PDF (157 KB) - MechanochemistryForce probes in a bottle

Subject Categories: Nanometrology and instrumentation | Structural properties

An electric current spike linked to nanoscale plasticity - pp287 - 291

Roman Nowak, Dariusz Chrobak, Shijo Nagao, David Vodnick, Michael Berg, Antti Tukiainen & Markus Pessa

doi:10.1038/nnano.2009.49

When a semiconductor is subjected to pressure, its mechanical and electrical properties change. Now, the observation of a previously undetected current spike during the nanoscale deformation of gallium arsenide calls for a significant revision of our understanding of nanoscale plasticity.

Abstract - | Full Text - An electric current spike linked to nanoscale plasticity | PDF (528 KB) - An electric current spike linked to nanoscale plasticity | Supplementary information

Subject Categories: Electronic properties and devices | Structural properties

Nanotubular metal–insulator–metal capacitor arrays for energy storage - pp292 - 296

Parag Banerjee, Israel Perez, Laurent Henn-Lecordier, Sang Bok Lee & Gary W. Rubloff

doi:10.1038/nnano.2009.37

Metal–insulator–metal electrostatic nanocapacitors can be fabricated in anodic aluminum-oxide nanopores using atomic layer deposition. This approach gives a planar capacitance of up to 100 F cm^-2 — substantially higher than previously reported values for nanostructured electrostatic capacitors.

Abstract - | Full Text - Nanotubular metal–insulator–metal capacitor arrays for energy storage | PDF (511 KB) - Nanotubular metal–insulator–metal capacitor arrays for energy storage | Supplementary information

Subject Categories: Electronic properties and devices | Synthesis and processing

Tunnelling readout of hydrogen-bonding-based recognition - pp297 - 301

Shuai Chang, Jin He, Ashley Kibel, Myeong Lee, Otto Sankey, Peiming Zhang & Stuart Lindsay

doi:10.1038/nnano.2009.48

DNA base pairs are held together by hydrogen bonds. It has now been shown that a scanning tunnelling microscope can be used to measure the strength of hydrogen bonding in such base pairs. These results provide a basis for new types of electronic biosensors and chemosensors.

Abstract - | Full Text - Tunnelling readout of hydrogen-bonding-based recognition | PDF (479 KB) - Tunnelling readout of hydrogen-bonding-based recognition | Supplementary information

Subject Categories: Electronic properties and devices | Nanosensors and other devices

A molecular force probe - pp302 - 306

Qing-Zheng Yang, Zhen Huang, Timothy J. Kucharski, Daria Khvostichenko, Joseph Chen & Roman Boulatov

doi:10.1038/nnano.2009.55

Force spectroscopy allows measurement of reaction rates as a function of the restoring force in molecules that have been stretched or compressed, but at present this approach lacks the temporal and spatial resolution to study systematically the reactivities of small functional groups. A molecular force probe — stiff stilbene — that extends force spectroscopy to the size scale of such reactions has now been reported.

Abstract - | Full Text - A molecular force probe | PDF (412 KB) - A molecular force probe | Supplementary information

Subject Categories: Nanometrology and instrumentation | Structural properties

See also: News and Views by Lenhardt & Craig

Three-dimensional imaging of short-range chemical forces with picometre resolution - pp307 - 310

Boris J. Albers, Todd C. Schwendemann, Mehmet Z. Baykara, Nicolas Pilet, Marcus Liebmann, Eric I. Altman & Udo D. Schwarz

doi:10.1038/nnano.2009.57

Chemical forces on surfaces have a central role in catalysis, thin-film growth and tribology. Many applications require knowledge of the strength of these forces as a function of position in three dimensions, but until now such information has only been available from theory. An approach based on atomic force microscopy has now been used to experimentally obtain this data, imaging the three-dimensional surface force field of graphite.

Abstract - | Full Text - Three-dimensional imaging of short-range chemical forces with picometre resolution | PDF (535 KB) - Three-dimensional imaging of short-range chemical forces with picometre resolution | Supplementary information

Subject Categories: Nanometrology and instrumentation | Surface patterning and imaging

Dopant profiling and surface analysis of silicon nanowires using capacitance–voltage measurements - pp311 - 314

Erik C. Garnett, Yu-Chih Tseng, Devesh R. Khanal, Junqiao Wu, Jeffrey Bokor & Peidong Yang

doi:10.1038/nnano.2009.43

Silicon nanowires could be central components in electronic and thermoelectric devices, but understanding nanowire surface properties and dopant distribution will be essential for making reproducible high-performance devices. Present methods for determining these parameters are problematic. Now, by using capacitance-voltage analysis, the radial profile and interface state density of silicon-nanowire field-effect transistors have been measured.

Abstract - | Full Text - Dopant profiling and surface analysis of silicon nanowires using capacitance–voltage measurements | PDF (249 KB) - Dopant profiling and surface analysis of silicon nanowires using capacitance–voltage measurements | Supplementary information

Subject Categories: Electronic properties and devices | Structural properties

Direct measurement of dopant distribution in an individual vapour–liquid–solid nanowire - pp315 - 319

Daniel E. Perea, Eric R. Hemesath, Edwin J. Schwalbach, Jessica L. Lensch-Falk, Peter W. Voorhees & Lincoln J. Lauhon

doi:10.1038/nnano.2009.51

The first direct measurements of dopant concentrations in arbitrary regions of individual nanowires are reported. Decomposition rates of heterogeneous precursors cause a heavily doped shell to surround an underdoped core. A thermodynamic model relating liquid and solid compositions to dopant fluxes is also presented.

Abstract - | Full Text - Direct measurement of dopant distribution in an individual vapour–liquid–solid nanowire | PDF (496 KB) - Direct measurement of dopant distribution in an individual vapour–liquid–solid nanowire | Supplementary information

Subject Category: Nanomaterials

See also: News and Views by Radovanovic

Phonon populations and electrical power dissipation in carbon nanotube transistors - pp320 - 324

Mathias Steiner, Marcus Freitag, Vasili Perebeinos, James C. Tsang, Joshua P. Small, Megumi Kinoshita, Dongning Yuan, Jie Liu & Phaedon Avouris

doi:10.1038/nnano.2009.22

Carbon nanotubes and graphene are potential components for nanoscale electronic devices, but power dissipation — a significant issue for high-density electronic circuits — is not fully understood in such materials. Researchers have now mapped the electrically excited phonon populations and the power dissipation pathways in a working carbon nanotube transistor.

Abstract - | Full Text - Phonon populations and electrical power dissipation in carbon nanotube transistors | PDF (560 KB) - Phonon populations and electrical power dissipation in carbon nanotube transistors | Supplementary information

Subject Categories: Carbon nanotubes and fullerenes | Electronic properties and devices

A DNA nanomachine that maps spatial and temporal pH changes inside living cells - pp325 - 330

Souvik Modi, Swetha M. G., Debanjan Goswami, Gagan D. Gupta, Satyajit Mayor & Yamuna Krishnan

doi:10.1038/nnano.2009.83

DNA nanomachines are synthetic DNA assemblies that switch between defined molecular conformations when stimulated by external triggers. So far, DNA devices have been limited to in vitro applications. A DNA nanomachine has now been constructed that can function as a pH sensor based on fluorescence resonance energy transfer (FRET) inside living cells.

Abstract - | Full Text - A DNA nanomachine that maps spatial and temporal pH changes inside living cells | PDF (572 KB) - A DNA nanomachine that maps spatial and temporal pH changes inside living cells | Supplementary information

Subject Categories: Molecular machines and motors | Nanosensors and other devices

See also: News and Views by Ishitsuka & Ha