CFN Colloquium

We have been developing atomic layer deposition (ALD) nanocomposite coatings comprised of conducting, metallic nanoparticles embedded in an amorphous dielectric matrix. These nanocomposite films have proved to be exceptional as resistive coatings in solid-state electron multipliers, as charge drain coatings, and as solar absorbing films in concentrated solar power. All of these applications demand tunable properties so that particular attributes of the film, such as electronic resistivity, can be precisely tailored for maximum efficiency. In our films, the properties are tuned by adjusting the ratio of metallic and dielectric components. For example, nanocomposite films comprised of W:Al2O3 are prepared using alternating exposures to trimethyl aluminum (TMA) and H2O for the Al2O3 ALD and alternating WF6/Si2H6 exposures for the W ALD. By varying the ratio of ALD cycles for the W and the Al2O3 components in the film, we can tune precisely the resistance of these coatings over a very broad range from 1012-105 Ohm-cm. We have used this strategy to synthesize a broad range of ALD nanocomposites combining different metals and dielectrics. These nanocomposite coatings have been utilized to functionalize capillary glass array plates and fabricate large-area microchannel plates suitable for application in large-area photodetectors. In addition, we have applied these films to serve as charge drain coatings in micro electro-mechanical systems (MEMS) devices for a prototype electron beam lithography tool, and obtained high-resolution electron beam patterns without charging artifacts. We have also used these nanocomposite coatings to infiltrate porous scaffolds resulting in selective solar absorbing coatings with high visible absorption and low IR emittance suitable for power tower receivers in concentrated solar power.


Bio Sketch: Dr. Jeffrey Elam is a Senior Chemist and Group Leader at Argonne National Laboratory where he directs a program in atomic layer depositi