Papers by Keyword: Nano-Films

Abstract: Nanostructures used to build current technology devices are generally based on the stack of several thin films (from few nanometer-thick to micrometer-thick layers) having different physical properties (conductors, semiconductors, dielectrics, etc.). In order to build such devices, thin film fabrication processes compatible with the entire device fabrication need to be developed (each subsequent process step should not deteriorate the previous construction). Solid-state reactive diffusion allows thin film exhibiting good interfacial properties (mechanical, electrical…) to be produced. In this case, the film of interest is grown from the reaction of an initial layer with the substrate on which it has been deposited, during controlled thermal annealing. In the case of the reaction of a nano-layer (thickness < 100 nm) with a semi-infinite substrate, nanoscale effects can be observed: i) the phases appear sequentially, ii) not all the thermodynamic stable phases appear in the sequence (some phases are missing), and iii) some phases are transient (they disappear as fast as they appear). The understanding of the driving forces controlling such nanoscale effects is highly desired in order to control the phase formation sequence, and to stabilize the phase of interest (for the targeted application) among all the phases appearing in the sequence.This chapter presents recent investigations concerning the influence of atomic transport on the nanoscale phenomena observed during nano-film reactive diffusion. The results suggest that nano-film solid-state reaction could be controlled by modifying atomic transport kinetics, allowing current processes based on thin-film reactive diffusion to be improved.

Abstract: LBL (layer by layer) fabrication was based on the electrostatic attraction between the nanosheets host partial with electric charges and external object with opposite charges. By changing the property of the object, level defects can also be introduced, so that the nano-films with remarkable physica-chemical properties can be prepared. Tantalum oxide and cobalt oxide nano-films materials were made via LBL self-assembly technology in this work

Abstract: Normal thermal conductivity of amorphous and crystalline SiO₂ nano-films is calculated by nonequilibrium molecular dynamics (NEMD) simulations in the temperature range from 100 to 700K and thicknesses from 2 to 6nm. The calculated temperature and thickness dependences of thermal conductivity are in good agreement with previous literatures. In the same thickness, higher thermal conductivity is obtained for crystalline SiO₂ nano-films. And more importantly, for amorphous SiO₂ nano-films, thickness can be any direction of x, y, z-axis without effect on the normal thermal conductivity, for crystalline SiO₂ nano-films, the different thickness directions obtain different thermal conductivity results. The different results of amorphous and crystalline SiO₂ nano-films simply show that film thickness and grain morphology will cause different effects on thermal conductivity.

Abstract: The Al2O3 nano-films of different thicknesses (1~100nm) were successfully deposited on the monocrystalline Si surface by using ion beam sputtering deposition. The surface topography and the component of nano-films with different thickness were analyzed. The quality of the surface of nano-films was systematically studied. When the films’ thickness increase, the studies by atomic force microscope (AFM), X-ray photoelectron spectrum（XPS） show that the gathering grain continually grows up and transits from acerose cellula by two-dimensional growth to globularity by three-dimensional growth. The elements O, Al and Si were found on the surface of Al2O3 nano-films. With the thickness of the films increasing, the content of Al gradually increases and the intensity peak of Si wears off, the surface quality of the deposited films is ceaselessly improved