Growth and Characterization of Self Assembled Palladium Oxide Nanostructures

Abstract

There is great interest in forming nanoscale structures through thermodynamically driven self-assembly processes. Self-assembled processes hold the promise of enabling the creation of complex, next-generation device architectures that rely on the intrinsic ability of the system to organize itself into ordered patterns. This is in contrast to the artificially ordered schemes, such as those currently used in integrated circuits. Many inorganic systems display microstructural evolution that resemble self-assembled processes, for example spinodal decomposition in alloys, dendrite formation in melts, and martensitic twins in metallic and ceramic alloys, where the assembly process is driven by thermodynamic and kinetic considerations. In this paper, we report on the self-assembly of nanometer-scale hillocks of conducting palladium oxide. We report the formation of periodic arrays of self-assembled hillocks upon oxidation of Pd films. The PdO₂ hillocks are referred to as “tips” due to their significantly large height (∼ 1νm) and conical shape. The tips are spaced ∼2.5μm apart and tip height is dependent on the film thickness, granularity and annealing conditions. The height and size of the PdO₂ tips increased and their distribution became narrow with increasing film thickness. We show that these structures can be fabricated on a number of substrates including silicon, glass, and various ceramic substrates.