Pulsed laser deposition and characterisation of ZnO and aluminium-doped ZnO nanostructures on silicon and flexible plastic substrates

摘要

We have developed recipes for the catalyst-free growth of upstanding/vertically aligned ZnO nanorods featuring core/shell or interconnected core/shell architectures on ZnO-seeded Si (100) substrates using the pulsed laser deposition (PLD) technique. The structural, morphological and luminescent properties of these ZnO nanorod samples were established. A ZnO emission band at 3.331 eV was observed in the core/shell and interconnected core/shell nanorod architectures and its origin linked to the defects observed at the crystalline/amorphous interface of the core/shell structure. This particular defect PL emission appears to be a new observation for ZnO.udWe have grown vertically aligned ZnO nanorods on PLD prepared ZnO-seeded Si substrates by catalyst-free vapour phase transport (VPT). The nanorods featured excellent optical properties and a coverage density higher than previously published data. The structural, morphological and luminescent properties of the seed layers and nanorods were inter-compared. Importantly, we also compared the near band edge emission of such VPT-and PLD-deposits, with a focus on the identification of the origin of the emission feature at 3.331 eV.udWe have researched the room temperature PLD growth of highly transparent and conductive ZnO and Al-doped ZnO (AZO) nanocrystalline thin films on flexible Zeonor plastic substrates. The trends for the growth rate, surface morphology, hydrophobicity and the structural, optical and electrical properties of 65 nm - 420 nm thick ZnO/AZO films grown on Zeonor substrates were analysed as a function of oxygen growth pressure (1-300 mTorr). The as-grown films showed highly reproducible deposition behaviour, and featured high transmittance, low-electrical resistance, optical smoothness, low residual stress, and hydrophobicity.udThe results presented in this thesis are discussed in the context of prospective