Sep 2, 2009
ZnS nanotubes available in template format
Zinc sulphide (ZnS) is a semiconductor with an energy bandgap of about 3.7 eV. Like its big brother ZnO, it is a material of choice in optoelectronics. So far, nanometer-scaled ZnS structures have been synthesized by a variety of techniques. Most of these involve high temperatures, possess less control over the size and the form of the fabricated structures and can sometimes involve complicated chemical routes. Atomic layer deposition (ALD) is a technique for the deposition of conformal, atomically precise, thin films.
Now, by employing a combination of ALD and electrochemical approaches, researchers in Germany have been able to deposit ZnS nanotubes with tunable wall thicknesses onto the pore walls of porous alumina templates at temperatures as low as 75 °C. The fabricated tubes have diameters in the range 20–200 nm, wall thicknesses down to just a few nanometers and their length can be in excess of 100 µm. In addition to paving the way for a variety of applications, the precise control over the size of the structures can be exploited for the investigation of generic size-dependent phenomena in solid-state systems. ZnS, like ZnO, may also hold promise for magnetic doping. Progress in this area could help developers gain a better understanding of low-dimensional magnetic semiconductors.
The researchers presented their work in Nanotechnology.
About the author
Dr Shadyar Farhangfar, a solid-state physicist, is currently working as a senior researcher in the Multifunctional Nanostructures group, led by Prof. Kornelius Nielsch, in the Institute of Applied Physics, University of Hamburg, Germany. His research interests include the theoretical and experimental investigation of transport phenomena in low-dimensional systems ranging from ultra-small tunnel junctions to carbon nanotubes to semimetallic nanowires. Recently he has been focusing on the electrochemical and atomic layer deposition of functional nanostructures. Ren Bin Yang, MSc in materials science, is a PhD student at the Max Planck Institute of Microstructure Physics in Halle. He is examining various routes towards the controlled synthesis of submicrometer-sized semiconductor structures. Marie Pelletier, currently at the Institute of Physical Chemistry, University of Hamburg, is completing her PhD thesis on the synthesis and characterization of ZnO nanoparticles.