30 March - Optical contrast in ion-implanted amorphous silicon carbide nanostructures

Tomorrow Tania will present the following paper

Optical contrast in ion-implanted amorphous silicon carbide nanostructures,

J.Phys.D, 40 (2007) 7492-7496.

Topographic and optical contrasts formed by Ga+ ion irradiation of thin films of amorphous silicon carbide have been investigated with scanning near-field optical microscopy. The influence of ion-irradiation dose has been studied in a pattern of sub-micrometre stripes. While the film thickness decreases monotonically with ion dose,  the optical contrast rapidly increases to a maximum value and then decreases gradually. The results are discussed

in terms of the competition between the effects of ion implantation and surface milling by the ion beam. The observed effects are important for uses of amorphous silicon carbide thin films as permanent archives in optical data storage applications.

Finding the Missing Memristor - R. Stanley Williams

R. Stanley Williams from HP Labs gives a keynote presentation on memristor technology at the UC San Diego Center for Networked System's Winter Research Review 2010.

A stretchable carbon nanotube strain sensor for human-motion detection 

Takeo Yamada,1 Yuhei Hayamizu,1Yuki Yamamoto,1Yoshiki Yomogida,1Ali Izadi-Najafabadi,1Don N. Futaba1& Kenji Hata

Devices made from stretchable electronic materials could be incorporated into clothing or attached directly to the body. Such materials have typically been prepared by engineering conventional rigid materials such as silicon, rather than by developing new materials. Here, we report a class of wearable and stretchable devices fabricated from thin films of aligned single-walled carbon nanotubes. When stretched, the nanotube films fracture into gaps and islands, and bundles bridging the gaps. This mechanism allows the films to act as strain sensors capable of measuring strains up to 280% (50 times more than conventional metal strain gauges), with high durability, fast response and low creep. We assembled the carbon-nanotube sensors on stockings, bandages and gloves to fabricate devices that can detect different types of human motion, including movement, typing, breathing and speech.

Nature Nanotechnology Year published: (2011) DOI: doi:10.1038/nnano.2011.36

23 March - Silicon Oxide: A Non-innocent Surface for Molecular Electronics and Nanoelectronics Studies

Today Peiman will present the following paper:

Silicon Oxide: A Non-innocent Surface for Molecular Electronics and Nanoelectronics Studies 

Jun Yao†, Lin Zhong*‡§, Douglas Natelson*§, and James M. Tour*‡ J. Am. Chem. Soc., 2011, 133 (4), pp 941–948

DOI: 10.1021/ja108277r 

Nanoelectronics: Flat transistors get off the ground

• Frank Schwierz

Nature Nanotechnology

 

6,

 

135–136

 

(2011)

 

doi:10.1038/nnano.2011.26

Published online

 

04 March 2011

The presence of a large bandgap means that a single layer of molybdenum disulphide can be used to make field-effect transistors with high on/off ratios and reasonably high mobilities.

16 March - A fast and low-power microelectromechanical system-based non-volatile memory device

Today Harish will present the following paper

A fast and low-power microelectromechanical system-based non-volatile memory device
Sang Wook Lee, Seung Joo Park, Eleanor E. B. Campbell & Yung Woo Park

Nature Communications Volume 2, published 01 March 2011
Article number: 220 - DOI: doi:10.1038/ncomms1227

Several new generation memory devices have been developed to overcome the low performance of conventional silicon-based flash memory. In this study, we demonstrate a novel non-volatile memory design based on the electromechanical motion of a cantilever to provide fast charging and discharging of a floating-gate electrode. The operation is demonstrated by using an electromechanical metal cantilever to charge a floating gate that controls the charge transport through a carbon nanotube field-effect transistor. The set and reset currents are unchanged after more than 11 h constant operation. Over 500 repeated programming and erasing cycles were demonstrated under atmospheric conditions at room temperature without degradation. Multinary bit programming can be achieved by varying the voltage on the cantilever. The operation speed of the device is faster than a conventional flash memory and the power consumption is lower than other memory devices.

VSM

Today's reading group will be on the VSM. Andy will present a small introduction on this popular technique used to characterize magnetic properties of materials.

The vibrating sample magnetometer: Experiences of a volunteer
S. Foner - Francis Bitter National Magnet Laboratory and Department of Physics, MIT, Cambridge, Massachusetts 02139

On its 40th anniversary, I describe how the vibrating sample magnetometer ~VSM! was developed and, later, how the very low frequency VSM, a flux-integration device, was developed. The important features of the moving sample technique, detection coil symmetry, calibration, sensitivity, and image effects are discussed briefly. Some VSM adaptations discussed include operation at 3He and dilution refrigerator temperatures, at high hydrostatic pressures, in superconducting, high-power water-cooled and hybrid magnets, for very low frequency ac susceptibility, and with SQUID detectors. © 1996 American Institute of Physics. [S0021-8979~96!50508-4]