The latest news from academia, regulators
research labs and other things of interest
Posted: Mar 25, 2014
High-quality nanometric bilayers prepared by aqueous solutions
(Nanowerk News) CIQUS researchers (Singular Center for Research in Biological Chemistry and Molecular Materials, USC, Spain), demonstrate that the chemical methods can compete with the physical ones to obtain homogeneous ultra-thin films and bilayers, from 4 nm, over large areas.
Quality comparison of the 15 nanometres layers obtained by PAD (chemical deposition) or PLD (pulsed laser deposition).
The synthesis of ultra-thin films and two-dimensional systems has become an essential element in the manufacture of different electronic devices. Physical deposition methods currently obtaining films with epitaxial growth (ie. perfectly ordered) and a controllable thickness, but they are very expensive and require highly specialized equipment (sputtering, PLD, MBE). While in the past decades many researchers have attempted to use chemical methods, they had not yet obtained a satisfactory quality, both morphologically and functional.
The research group has published several works which demonstrate overcoming three major drawbacks of chemical deposition techniques for two-dimensional nanoscale systems. On the one hand because the roughness is extremely low, a second layer can be deposited maintaining a perfectly defined interface between layers. Moreover, the growth of two layers is epitaxial. On the other hand a total control of the stoichiometry (chemical composition) is maintained and finally, it has been achieved to deposit over areas of several square centimeters, completely free of defects.
Specifically, they have deposited two layers of lanthanum oxides (manganese and cobalt), with a controlled thickness of only 18 and 4 nanometres, respectively.