Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Innovative nanomaterials processing points to advances in semiconductor optoelectronics

15.11.2005


Electron diffraction pattern of PbS nanoparticles in zeolite X


Optical and structural properties of PbS nanoparticles produced in Zeolite Na-X

The study of semiconductor nanoparticles embedded in a matrix is currently a very active research area. These small particles have physicochemical properties quite different from those in the bulk material. A great variety of semiconductors nanoparticles have been synthesized in different matrix such as polymers, glasses and zeolites with the main purpose to modify their properties by controlling the particle size. Alterations to these properties mean they can be tailored to specific applications in the fields of non-linear optics, photovoltaic conversion, catalysis, optoelectronics, etc.

In this work, published in AZojomo*, by M. Flores-Acosta, R. Pérez-Salas, M. Sotelo-Lerma, F. F. Castillón-Barraza and R. Ramírez-Bon from Unidad Querétaro, Universidad de Sonora and Universidad Nacional Autónoma de México, PbS nanoparticles were synthesized in zeolite Na-X by means of ionic exchange processes in alkaline aqueous solutions. They reported the optical and structural properties of the system PbS-Na-X zeolite.



The 4.0nm PbS nanoparticles have spherical shape, the crystalline structure of galena and are embedded uniformly in the zeolite matrix. The 1se-1ph and 1pe-1ph excitonic transitions observed in the absorption spectra of the PbS-Na-X system is explained in terms of the crystalline quality of the PbS nanoparticles.

The results show that spherical PbS nanoparticles are formed not inside the zeolite cages but outside, embedded in the zeolite matrix. The absorption spectra of the samples display exciton absorption bands at much higher energy than the fundamental absorption edge of bulk PbS. This result is a consequence of strong quantum confinement effects produced by the reduced size of the PbS nanoparticles as compared to the exciton Bohr diameter of bulk PbS.

Dr. Ian Birkby | EurekAlert!
Further information:
http://www.azonetwork.com

More articles from Physics and Astronomy:

nachricht Computer model predicts how fracturing metallic glass releases energy at the atomic level
20.07.2018 | American Institute of Physics

nachricht What happens when we heat the atomic lattice of a magnet all of a sudden?
18.07.2018 | Forschungsverbund Berlin

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Future electronic components to be printed like newspapers

A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.

The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

A smart safe rechargeable zinc ion battery based on sol-gel transition electrolytes

20.07.2018 | Power and Electrical Engineering

Reversing cause and effect is no trouble for quantum computers

20.07.2018 | Information Technology

Princeton-UPenn research team finds physics treasure hidden in a wallpaper pattern

20.07.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>