1. UKM Learning and Research Repository
2. PHD Thesis / Tesis PHD
3. Institute of Microengineering and Nanoelectronics / Institut Kejuruteraan Mikro dan Nanoelektronik (IMEN)

Title:	Growth and characterization of well aligned catalyst free ZnO nanowires
Authors:	Karamdel Javad (P39873)
Supervisor:	Burhanuddin Yeop Majlis, Prof. Dr. Dato
Keywords:	Nanowires Nanostructured materials
Issue Date:	30-May-2011
Description:	Recently, one-dimensional (1-D) nanomaterials have become the focus point in nanoscience and nanotechnology due to their novel and extraordinary properties and wide range of applications. ZnO nanostructures are among the most important 1-D nanomaterials due to their wide band gap energy (3.37eV at room temperature), large exciton binding energy (60 meV), high optical performance and piezoelectric properties. Moreover, ZnO represents a wide range of 1-D structures such as nanorods, nanowires, nanobelts, nanohelices, etc., which are potential building blocks for fabricating nanodevices. This work represents the synthesis, characterization and photoluminescence properties of well aligned and catalyst free ZnO nanowires with an improved PVD system. This new set up is as simple as the conventional PVD technique and works in atmospheric pressure. For growing well controlled ZnO nanostructures and avoiding unintentional contamination arisen from metal catalysts, various thin films with close lattice constant to ZnO were utilized as the buffer layer instead of a metallic catalyst layer or a lattice-mismatched Si and an Al2O3 substrate. A wide range of nanostructures such as nanorods, nanowires, nanocombs, nanobelts, nanospheres, etc. are synthesized by control of growth parameters. The nanowires which are synthesized by this novel PVD set up in absence of any catalyst are well aligned with a perfect crystallinity and ultrafine photoluminescence properties that make them a potential structure having superior performance in optical applications. For realization of these achievements, firstly, various thin films such as ZnO, aluminium doped ZnO, nitrogen doped ZnO and AlN are sputtered on different substrates and then are characterized to find the optimum conditions of deposition and treatment for harvesting desired buffer layers. Subsequently, these buffer layers are employed to grow ZnO nanowires on them by the novel PVD method. The grown nanostructures are then characterized by FESEM, EDX, XRD, TEM, HRTEM, Raman Spectroscopy and PL spectroscopy. From characterization of products, it is found out that the optical properties and alignment of the nanowires are influenced by the properties of buffer layer, for example, by proper adjustment of the buffer layer the interface defects have been minimized, in which in the PL spectra only one peak at UV region (around 380 nm) is observed which corresponds with near band edge emission. Moreover, doped ZnO nanowires are successfully grown and their characterization reveals that the UV peak can be positioned by different types and rates of dopants. Finally, by control of growth condition, the morphology of ZnO nanowires are controlled, in which sharp or wide tip nanowires that can be utilized in different applications are synthesized.,PhD
Pages:	213
Call Number:	TK7874.85.K337 2011 tesis
Publisher:	UKM, Bangi
Appears in Collections:	Institute of Microengineering and Nanoelectronics / Institut Kejuruteraan Mikro dan Nanoelektronik (IMEN)

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