A research study submitted in partial fulfillment of the requirements for the degree of Master of Engineering in Microelectronics, School of Engineering and Technology

Thesis (M.Eng.) - Asian Institute of Technology, 2009

Nanometer-sized particles (gold and zinc sulphide) are considered to be the mostimportant fundamental building blocks for the future discrete electronic devices. Colloidalnano particles ( 20 nm) are differentiated from much smaller particles (molecules) because{u223C}their intrinsic properties still usually resembles with a bulk-like behavior. Nano crystallinethin films have been the subject of huge scientific and technological efforts over the pasttwo decades due to their interesting physicochemical, mechanical and electrical properties.The fabrication of alternate metal and insulator multilayer present numerous feasibleapplications in electronic devices (diodes, transistors, electronic memories, etc).However,there are numerous challenges and questions regarding the stability of the nano particles incolloids, thickness and quality of the thin films, that must be addressed before nanoparticletechnologies can be implemented successfully.Attempts were made to understand andcontrol nanoparticle aggregation processes that have been brought about using concepts ofmolecular recognition.New methods for assembling nanoparticles together into multilayerdevices with more complex electronic functions are also required.This study highlights our recent progress toward characterizing thin layerfabrication using electrostatically stabilized gold nanoparticles as a function of cappingcharge state while zinc sulphide was electrosterically stablised by chitoson (a bio polymer).The idea of introducing the buffer solutions (acetate and citrate) between the alternatedepositing of metal (Gold) and insulator (ZnS) bi-layers helped to remove the aggregationof these nanoparticles. The experiments that performed, have concluded that by controllingthe concentration and pH of the colloidal solutions, a remarkable improvement is observedin the electrical and optical properties of deposited layers.The possibility of fabricating thin films has opened new horizons to find practicalapplications of these devices in future microelectronic circuits.