Study On The Growth Mechanism And Properties Of Aluminum Nanostructure On Silicone Oil Surfaces

Fabrication, characterization and application of nanostructures are important topic of nanoscience and nanotechnology. Researches on nanostructures fabricated on solid substrates are quite flourish. At the same time, fabricating nanostructures on liquid substrate is a new subject in nanoscience and nanotechnology. Compared with solid substrate, liquid substrate has some peculiar properties:weak interaction between liquid substrate and nanostructures, larger diffusion coefficient than that of the solid substrate, isotropic property due to the non-lattice characteristic. Therefore, the nanostructures grown on liquid substrates possess characteristic growth mechanism, microstructure and properties. Up until now, a lot of problems are still unsolved and more work are needed, for example, in-situ observation of the growth of nanostructures on liquid substrate, etc.In this dissertation, we fabricate aluminum (Al) nanostructures on silicon oil surfaces by thermal evaporation method. After transferring the A1 nanostructures onto leaved mica or polished silicon wafer, we systematically study the evolution of growth mechanism, morphology and microstructure of the Al nanostructures with nominal film thickness and substrate temperature by means of atomic force microscopy (AFM).The experimental results show that, the growth mechanism of the Al nanostructures obeys the two-stage growth model. Al NPs exhibit two-dimensional aggregation behavior on the silicone oil surfaces, which makes exploration of the material density evolution of A1 NPs possible.Under the same substrate temperature (Ts), as the nominal film thickness increases from 0.02 nm to 0.18 nm, the average diameter and height of the A1 NPs didn’t change significantly and are in the range of 30±10 nm and 2.5±1.2 nm, respectively. On the other hand, the coverage exhibits a fluctuant nonlinear increase behavior from 20% to 80%, implying the material density of A1 NPs increases in this process.With the same nominal film thickness, we investigate the evolution of Al nanostructures under different Ts. As Ts increased from 293 K to 393 K, the morphology of the Al nanostructures change from ramified aggregates to separated NPs. The average diameter and height of the Al NPs increase from 13 nm to 28 nm and 2.3 nm to 7.6 nm, respectively, illustrating that the morphology change from disk-shaped to sphere-shape gradually. This process can be described by a two-dimensional diffusion and coalescence model.The contents of this dissertation are organized as below:In chapter 1, firstly, we briefly review the fabrication, characterization and application of nanostructure. Then, the study of nanostructure on liquid substrate is summarized. Finally, the research purpose and content of this dissertation is presented.In chapter 2, we systemically study the morphology and microstructure evolution of the Al nanostructures with the nominal film thickness by means of AFM.In chapter 3, by varying the substrate temperature, microstructure evolution of the A1 NPs are studied. The increase of the Al NPs’ volume can be explained by a two-dimensional diffusion and coalescence model.In chapter 4, the dynamic scaling behavior of the A1 nanostructures is studied.In chapter 5, based on the experimental and theoretical results, the main conclusions and prospects are presented.