from the smoothing-your-adatoms dept.
Researchers devise approach to anchor metals to metal oxides, a press release from Pacific Northwest National Laboratory, describes work done at PNNL and Sandia National Laboratory to deposit on a metal oxide layer a flat layer of metal atoms, only a few atoms thick, despite the large mismatch between the lattice constants of the metal and the metal oxide layers. The technology is expected to find use in magnetic tunnel junctions, slated for use in magnetoresistive random access memory, or MRAM, and in lowering the costs of catalysts because it will be possible to use thinner layers of expensive metals.
The press release continues, the discovery may also "provide the molecular insight industry needs to create better materials for microelectronics and sensors." The research was published in the August 2, 2002 issue of Science 297, pp. 827-831:
Laminar Growth of Ultrathin Metal Films on Metal Oxides: Co on Hydroxylated α-Al2O3(0001)
S. A. Chambers, T. Droubay, D. R. Jennison, T. R. Mattsson
Metals deposited in vacuum on metal oxides such as alumina normally grow as three-dimensional clusters because of weak adatom-substrate interactions. This tendency hinders our ability to form interfaces of ultrathin, laminar metal films on oxides for use in microelectronics and other technologies where nanostructural control is desired. We present experimental and theoretical results showing that room temperature Co deposition on fully hydroxylated clean sapphire (α-Al2O3) produces a surface chemical reaction that leads to laminar growth, despite a large mismatch in lattice constants. This process should be applicable to a wide range of metals and metal oxides.
