Nanowires get into the groove

Aug 22, 2011

Weizmann Institute scientists have discovered that growing nanowires out, not up, can keep them in line.

Growing up is not easy, especially for tiny nanowires: With no support or guidance, nanowires become unruly, making it difficult to harness their full potential as effective semiconductors. Prof. Ernesto Joselevich of the Weizmann Institute's Chemistry Faculty has found a way to grow semiconductor nanowires out, not up, on a surface, providing, for the first time, the much-needed guidance to produce relatively long, orderly, aligned structures. Since semiconductors with controlled structures are at the core of the most advanced technologies, this new research will hopefully enable the production of semiconductor nanostructures with enhanced electronic and , suitable for a wide range of applications including LEDs, lasers, information , , computers, and more.

Joselevich, Ph.D. student David Tsivion and postdoctoral fellow Mark Schvartzman of the Materials and Interfaces Department grew nanowires made of (GaN) using a method that usually produces vertical nanowires with excellent optical and electronic properties. These vertical wires only become unruly once they are harvested and assembled into arrays. To bypass this problem, the scientists used sapphire as a base on which to grow the nanowires. But rather than growing them on a smooth surface, deliberately cut the sapphire along different planes of the crystal, resulting in various surface patterns including 'steps' of nano-meter dimensions between the different planes of the crystal, as well as accordion-like, V-shaped grooves.

Their results, recently published in Science, show that surface steps and grooves have a strong guiding effect, coaxing the nanowires to grow horizontally along their edges or within the grooves and producing well-aligned, millimeter-long nanowire arrays. In contrast, current methods of assembling nanowires horizontally on smooth surfaces result in disorderly nanowires only micrometers in length with subpar properties.

Joselevich: 'It was surprising to discover that the optical and of our nanowires were just as good – if not better – than those grown vertically, because growing semiconductors on a surface usually introduces defects that degrade their quality.'

Although it is still not fully clear how a method that normally produces vertical nanowires works to create horizontal growth in the new study, Joselevich and his team have managed to combine, in a single step, the synthesis and assembly of well-structured nanowires with unique properties suitable for a wide range of applications, by simply getting them 'into the groove.' ?

Explore further: NIST offers electronics industry two ways to snoop on self-organizing molecules

add to favorites email to friend print save as pdf

Related Stories

Low-Temperature Growth and Properties of ZnO Nanowires

Jun 01, 2004

Xuan Wang et al. from Peking University, China report in the last issue of Applied Physics Letters about ZnO nanowires grown through evaporation of zinc powders under a low temperature of 400 C. Being about 10 ...

Great potential with new ultra-clean nanowires

Nov 09, 2010

New ultra-clean nanowires produced at the Nano-Science Center, University of Copenhagen will have a central role in the development of new high-efficiency solar cells and electronics on a nanometer scale. ...

Recommended for you

Quantum effects in nanometer-scale metallic structures

15 hours ago

Plasmonic devices combine the 'super speed' of optics with the 'super small' of microelectronics. These devices exhibit quantum effects and show promise as possible ultrafast circuit elements, but current ...

User comments : 0