Free Newsletters - Space - Defense - Environment - Energy - Solar - Nuclear
..
. Nano Technology News .




NANO TECH
Nanosheets and nanowires
by Staff Writers
Beijing, China (SPX) Apr 03, 2014


This is a typical TEM image of as-prepared GeS nanowires with the inset showing a selected area electron diffraction pattern taken from GeS nanowires. Image courtesy Liang Shi and Yumei Dai.

Researchers in China, have found a convenient way to selectively prepare germanium sulfide nanostructures, including nanosheets and nanowires, that are more active than their bulk counterparts and could open the way to lower cost and safer optoelectronics, solar energy conversion and faster computer circuitry.

Germanium monosulfide, GeS, is emerging as one of the most important "IV-VI" semiconductor materials with potential in opto-electronics applications for telecommunications and computing, and as an absorber of light for use in solar energy conversion. One important property is its much lower toxicity and environmental impact when compared to other semiconductors made with cadmium, lead and mercury.

It is less costly than other materials made with rare and noble metal elements. Indeed, glassy GeS has been used in lasers, fibre optic devices and infrared lenses as well as rewritable optical discs and non-volatile memory devices for several years. It is also used extensively as a solid electrolyte in conductive bridging random access memory (RAM) devices.

The repertoire of this material might be extended much further with the extra control that its use as nanostructured systems might allow. Liang Shi and Yumei Dai of the University of Science and Technology of China, in Hefei, point out that research in this area has lagged behind that with other IV-VI semiconductors.

They hope to change that and have focused on how nanosheets and nanowires of GeS might be readily formed. They have used X-ray powder diffraction, transmission electron microscopy, energy-dispersive X-ray spectrometry and scanning electron microscopy to investigate the structure, morphology, composition and optical absorption properties of their samples.

The team used simple "wet" chemistry to synthesis their products using germanium dichloride-dioxane complex, thiourea and oleylamine (OLA) as starting materials. The ingredients were mixed in a sealed reaction flask, blasted with ultrasound to exclude air and then stirred and heated. The team was able to make nanosheets of GeS this way if the process was carried out for several hours at 593 Kelvin.

At higher temperature, 613 Kelvin, they found that the sheets wind up into nanowires. Indeed, the precise heating time and temperature allowed them to control the structure of the final product. The team suggests that the rolling up of the nanosheets into nanowires is driven by the surface tension between the sheet and the OLA molecules during the heating.

Having proven the structural integrity of their GeS nanowires and nanosheets, the team built several test devices - a photoresponsive unit - which they used to evaluate the optical and electronic properties of the products.

The team says that they have demonstrated "outstanding photoresponsive behaviour". This "indicates the potential use of as-synthesized GeS nanosheets and nanowires in solar energy conversion systems, such as the fabrication of photovoltaic devices".

[J. Appl. Cryst. (2014). 47, 527-531]

.


Related Links
International Union of Crystallography
Nano Technology News From SpaceMart.com
Computer Chip Architecture, Technology and Manufacture






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News



International Conference on Protection of Materials and Structures From Space Environment



NANO TECH
Fabricating Nanostructures with Silk Could Make Clean Rooms Green Rooms
Somerville MA (SPX) Apr 01, 2014
Tufts University engineers have demonstrated that it is possible to generate nanostructures from silk in an environmentally friendly process that uses water as a developing agent and standard fabrication techniques. This approach provides a green alternative to the toxic materials commonly used in nanofabrication while delivering fabrication quality comparable to conventional synthetic polymers. ... read more


NANO TECH
Philippines buying new helicopters

Philippines orders Korean jet fighters

Ukraine delivers upgraded military transports to India

Fleet Complete!

NANO TECH
China launches experimental satellite

Tiangong's New Mission

"Space Odyssey": China's aspiration in future space exploration

China to launch first "space shuttle bus" this year

NANO TECH
CyberPoint international joins Lockheed's Cyber Security Alliance

Google says Turkey intercepting its Web domain

Keeping secrets in a world of spies and mistrust

US 'restrained' in cyber operations - Pentagon chief

NANO TECH
U.S. House puts energy at top of budget plan

British greenhouse gas emissions decline

GDF Suez starts operations at Omani power plants

BTM Reduces Coolant Usage and Waste Removal Costs with QualiChem Fluids

NANO TECH
Rainbow-catching waveguide could revolutionize energy technologies

Anadarko Petroleum to pay $5.15 bn in pollution case

Russia's Tatneft plans Libyan return

Two percent of Canada's oil gets to overseas markets

NANO TECH
Ukrainian industry ready to supply military with armored vehicles

Eaton intros power micro-grid system for forward-deployed troops

Rockwell Collins, Avionics Services in manufacturing deal

Cassidian receives order for military optics

NANO TECH
Fabricating Nanostructures with Silk Could Make Clean Rooms Green Rooms

Scientists watch nanoparticles grow

Nanotube coating helps shrink mass spectrometers

Researchers Grow Carbon Nanofibers Using Ambient Air, Without Toxic Ammonia

NANO TECH
Scientists unveil 'BionicKangroo Robot'

Robotic arm probes chemistry of 3-D objects by mass spectrometry

'RoboClam' replicates a clam's ability to burrow while using little energy

As Age-Friendly Technologies Emerge, Experts Recommend Policy Changes




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.