Molecular assembly based nano-composite structures for memory applications

Abstract

With the objective of improving performance of current nonvolatile organic memories in terms of enhanced stability and developing memory devices with dimensions much smaller than those of current technologies, this Ph.D. thesis is focused on formation of molecular assembly based thin films of organic and organic-metallic structures for nonvolatile memory applications. Nonvolatile organic memory devices utilizing solution processed uniformly distributed copper nanoparticles in polyimide matrix have been fabricated and their unique electrical properties are discussed. The Langmuir-Blodgett technique has been employed in fabricating a multilayered array of gold nanoparticles on silicon substrates and increase in charge storage capacity with number of layers has been demonstrated. Functionalized gold nanoparticles have been immobilized on to silicon surfaces through covalent molecular assembly. The charge storage capability for such covalently bound gold nanoparticles has also been demonstrated. Multilayered composite films comprising functionalized polymer and gold nanoparticles with controlled inter-layer separation have been demonstrated. A novel route towards fabricating high-density assemblies of gold nanoparticles over large areas has been demonstrated. The resulting gold nanoparticle assemblies over patterned gold nanoparticle arrays showed better charge storage capacity over un-patterned gold counterparts with comparable particle densities. Apart from showing the feasibility of layer-wise molecular assembly with interlayer covalent bonding, this work demonstrates a promising alternative to conventional spin coating based organic nonvolatile memory devices.