Featured Research

from universities, journals, and other organizations

Hybrid nanostructures: Getting to the core

Date:
June 19, 2013
Source:
The Agency for Science, Technology and Research (A*STAR)
Summary:
Material scientists expect the new multifunctional properties of hybrid nanostructures will transform the development of high-performance devices, including batteries, high-sensitivity sensors and solar cells. These self-assembling nanostructures are typically generated by depositing ultrasmall objects with different properties on the surfaces of tiny semiconducting wires. However, the factors that govern their formation remain elusive, making these structures difficult to control and design.

Material scientists expect the new multifunctional properties of hybrid nanostructures will transform the development of high-performance devices, including batteries, high-sensitivity sensors and solar cells. These self-assembling nanostructures are typically generated by depositing ultrasmall objects with different properties on the surfaces of tiny semiconducting wires. However, the factors that govern their formation remain elusive, making these structures difficult to control and design.

Related Articles


To fill this gap, Bharathi Srinivasan and co-workers from the A*STAR Institute of High Performance Computing have developed a computational approach that sheds light on the self-assembly of these nanostructures on multi-sided, or polygonal, nanowires. They first identified how different nanostructure patterns grow on nanowires by conducting energy calculations in a theoretical analysis before analyzing these patterns by performing numerical simulations.

Srinivasan's team designed two- and three-dimensional (2D and 3D) models of nanowires with a square, hexagonal or octagonal core surrounded by various shell configurations. Analysis of the energy profiles of these configurations showed that the researchers could control shell morphology by changing the core size. The theoretical analysis also revealed the transitions between these different configurations -- a valuable insight into the self-assembly mechanism.

For the numerical simulation, the researchers constructed a 'phase-field' model, which mathematically defined the phase transitions of the shell material. This allowed them to simulate the self-assembly process of the nanostructures on the nanowires after depositing the 'seed' in the form of 'quantum dots', which are miniature semiconductors. The equations used in the simulation describe both the thermodynamics and the kinetics of self-assembly, Srinivasan notes.

Both the 2D and 3D simulations showed that the deposited shells underwent morphological transformations that mirrored the energy calculations. At the initial deposition stage -- the lowest size range -- the shells consisted of perfect cylinders in the 2D model, and they formed ultrasmall rings, or 'nanorings', stacked along the vertical direction of the nanowire, in the 3D model.

As the core expanded, the 2D models indicated that the shells could break into smaller wires. For the intermediate-sized cores, each wire sat on the sides of the core. For the largest-sized cores, they sat on the corners. In the 3D simulations, the nanorings divided into quantum dots that materialized into columns on the nanowire facets and migrated towards the ridges upon further growth (see image). Simulations of heat treatment yielded the same configurations as those during growth.

"Our future work [will be] to understand the growth of different hybrid nanostructures, including quantum dots on shells, nanorings and other quantum dots," says Srinivasan.


Story Source:

The above story is based on materials provided by The Agency for Science, Technology and Research (A*STAR). Note: Materials may be edited for content and length.


Journal Reference:

  1. Liang-Xing Lu, M. S. Bharathi, Yong-Wei Zhang. Self-Assembly of Ordered Epitaxial Nanostructures on Polygonal Nanowires. Nano Letters, 2013; 13 (2): 538 DOI: 10.1021/nl3040543

Cite This Page:

The Agency for Science, Technology and Research (A*STAR). "Hybrid nanostructures: Getting to the core." ScienceDaily. ScienceDaily, 19 June 2013. <www.sciencedaily.com/releases/2013/06/130619161544.htm>.
The Agency for Science, Technology and Research (A*STAR). (2013, June 19). Hybrid nanostructures: Getting to the core. ScienceDaily. Retrieved March 6, 2015 from www.sciencedaily.com/releases/2013/06/130619161544.htm
The Agency for Science, Technology and Research (A*STAR). "Hybrid nanostructures: Getting to the core." ScienceDaily. www.sciencedaily.com/releases/2013/06/130619161544.htm (accessed March 6, 2015).

Share This


More From ScienceDaily



More Matter & Energy News

Friday, March 6, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Driverless Budii Gives the Wheel Feel

Driverless Budii Gives the Wheel Feel

Reuters - Business Video Online (Mar. 6, 2015) The Rinspeed Budii Concept car is creating a driverless stir at this year&apos;s Geneva car show. It&apos;s an all-electric autonomous vehicle with a difference. Ciara Lee reports. Video provided by Reuters
Powered by NewsLook.com
Star Wars Inspires Mobile Holograms

Star Wars Inspires Mobile Holograms

Reuters - Business Video Online (Mar. 6, 2015) 3D holograms could soon be coming to your mobile phone. Inspired by the famous Princess Leia hologram from Star Wars, a U.S. company is showcasing a prototype display at the Mobile World Congress at Barcelona and says it could be used for real-time video calls. Ivor Bennett reports Video provided by Reuters
Powered by NewsLook.com
Game Makers Lured Into Virtual Worlds

Game Makers Lured Into Virtual Worlds

AFP (Mar. 6, 2015) Some 25,000 people have descended upon San Francisco to show off the latest technologies and video games at the Game Developers Conference. Developers here discuss the future of the industry. Duration: 02:20. Video provided by AFP
Powered by NewsLook.com
Gas Production Cut on Earthquake Fears

Gas Production Cut on Earthquake Fears

Reuters - Business Video Online (Mar. 5, 2015) The Dutch government has cut production at Europe&apos;s largest gas field in Groningen amid concerns over earthquakes which are damaging local churches. As Amy Pollock reports the decision - largely politically-motivated - could have big economic conseqeunces. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins