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1.
A nearly free sustained copper (Cu) film system has been successfully fabricated by thermal evaporation deposition of Cu atoms on silicone oil surfaces, and a characteristic ordered pattern has been systematically studied. The ordered pattern, namely, band, is composed of a large number of parallel key-formed domains with different width w but nearly uniform length L; its characteristic values of w and L are very susceptible to the growth period, deposition rate and nominal film thickness. The formation mechanism of the ordered patterns is well explained in terms of the relaxation of the internal stress in the films, which is related to the nearly zero adhesion of the solid-liquid interface. By using a two-time deposition method, it is confirmed that the ordered patterns really form in the vacuum chamber.  相似文献   

2.
A series of amorphous and single-crystalline LaAlO3 (LAO) thin films are fabricated by laser molecular-beam epitaxy technique on Si substrates under various conditions of deposition. The structure stability of the LAO films annealed in high temperature and various ambients is studied by x-ray diffraction as well as high-resolution transmission electron microscopy. The results show that the epitaxial LAO films have very good stability, and the structures of amorphous LAO thin films depend strongly on the conditions of deposition and post-annealing. The results reveal that the formation of LAO composition during the deposition is very important for the structure stability of LAO thin films.  相似文献   

3.
Highly repeatable multilevel bipolar resistive switching in Ti/Ce Ox/Pt nonvolatile memory device has been demonstrated. X-ray diffraction studies of Ce O2 films reveal the formation of weak polycrystalline structure. The observed good memory performance, including stable cycling endurance and long data retention times(〉10^4s) with an acceptable resistance ratio(~10^2), enables the device for its applications in future non-volatile resistive random access memories(RRAMs). Based on the unique distribution characteristics of oxygen vacancies in Ce Ox films, the possible mechanism of multilevel resistive switching in Ce Ox RRAM devices has been discussed. The conduction mechanism in low resistance state is found to be Ohmic due to conductive filamentary paths, while that in the high resistance state was identified as Ohmic for low applied voltages and a space-charge-limited conduction dominated by Schottky emission at high applied voltages.  相似文献   

4.
AgInSbTe/Si thin films on glass substrates are prepared by dc magnetron sputtering at room temperature. Using Si underlayer as the thermal diffusion layer, the super-resolution nano-ablation holes with a size of 70hm in the AglnSbTe phase change films are obtained by a far-field focused laser experimental setup, with laser wavelength 405 nm and objective-lens numerical aperture 0.90. The nano-ablation formation mechanism is analysed and discussed via the thermal diffusion of sample structures.  相似文献   

5.
The excimer laser-induced crystallization technique has been used to investigate the preparation of nanocrystalline silicon(nc-Si) from amorphous silicon(α-Si) thin films on silicon or glass substrates.The α-Si films without hydrogen grown by pulsed -laser deposition are chosen as precursor to avoid the problem of hydrogen effluence during annealing,Analyses have been performed by scanning electron microscopy,atomic force microscopy,Raman scattering spectroscopy and high-resolution transmission-electron microscopy.Experimental results show that silicon nanocrystals can be formed through laser annealing.The growth characters of nc-Si are strongly dependent on the laser energy density.It is shown that the volume of the molten silicon predominates essentially the grain size of nc-Si,and the surface tension of the crystallized silicon is responsible for the mechanism of nc-Si growth.  相似文献   

6.
The refractive indices of thin films, containing dielectric and voids in an oblique columnar structure, are modelled in the quasi-static limit. The dielectric function is shown to be strongly dependent on the angle of incidence and on the columnar orientation for p-polarized light. This model is applied to model ZnS thin films with oblique columnar structures and the computed results have been given.  相似文献   

7.
The boron-oxygen-nitrogen(BON) films have been grown on Si wafer by the low-frequency rf-plasma-enhanced metal-organic chemical vapour deposition method.The homogeneous film structure of completely amorphous BON is first fabricated on a low-temperature-made buffer at 500℃ with N2 plasma and is observed with a highresolution-electron microscope by the transmission-electron diffraction.The results show that the interfaces among substrate/buffer/film are clear and straight in the structured film.A heterogeneous film containing nano-sized crystalline particles is also grown by a routine growth procedure as a referential structure,The C-V characteristic is measured on both the amprphous and crystal-containing films by using the metal-oxidesemiconductor structure,The dielectric constants of the films are,therefore,deduced to be 5.9 and 10.5 for the amorphous and crystal-containing films,respectively,The C-V results also indicate that more trapped charges exist in the amorphous film.The binding energy of the B,O.and N atoms in the amprphous film is higher than that in the crystal-containing one,and the N-content in the latter is found to be higher than that in the former by x-ray photo-electron spectroscopy.The different electrical Property of the films is thought to originate from the energy state of the covalent electrons.  相似文献   

8.
A systematic study on the structures and electronic properties of copper clusters has been performed using the density functional theory. In the calculation, there are many isomers near the ground state for small copper clusters. Our results show that the three-dimensional isomers of copper clusters start from Cu7 cluster and then show a tendency to form more compact structures. The results of the formation energy and the second derivative of binding energy with duster size show that besides N = 8, N =11 is also a magic number. Furthermore, it is the first time to find that the ground state of 11-atom clusters is a biplanar structure as same as the 13-atom cluster. The clear odd-even alternation as cluster size for the formation energy indicates the stability of electronic close shell existed in the range studied.  相似文献   

9.
To increase corrosion resistance of the sample,its electrical impedance must be increased.Due to the fact that electrical impedance depends on elements such as electrical resistance,capacitance,and inductance,by increasing the electrical resistance,reducing the capacitance and inductance,electrical impedance and corrosion resistance can be increased.Based on the fact that these elements depend on the type of material and the geometry of the material,multilayer structures with different geometries are proposed.For this purpose,conventional multilayer thin films,multilayer thin film including zigzag structure(zigzag 1)and multilayer thin film including double zigzag structure(zigzag 2)of manganese nitride are considered to protect AISI 304 stainless steel against corrosion in salt solution.These multilayer coatings including zigzag structures are prepared by alternately using the conventional deposition of thin film and glancing angle deposition method.After deposition,the samples are placed in a furnace under nitrogen flux for nitriding.The cross sections of the structures are observed by field emission scanning electron microscopy(FESEM).Atomic force microscope(AFM)is used to make surface analyses of the samples.The results show that the multilayer thin films including zigzag structures have smaller grains than conventional multilayer thin films,and the zigzag 2 structure has the smaller grain than the other two samples,which is attributed to the effect of shadowing and porosity on the oblique angle deposition method.Crystallography structures of the samples are studied by using x-ray diffraction(XRD)pattern and the results show that nitride phase formation in zigzag 2 structure is better than that in zigzag 1 structure and conventional multilayer thin film.To investigate the corrosion resistances of the structures,electrochemical impedance spectroscopy(EIS)and potentiodynamic polarization tests are performed.The results reveal that the multilayer thin films with zigzag structures have better corrosion protection than the conventional multilayer thin films,and the zigzag structure 2 has the smallest corrosion current and the highest corrosion resistance.The electrical impedances of the samples are investigated by simulating equivalent circuits.The high corrosion resistance of zigzag 2 structure as compared with conventional multilayer structure and zigzag 1 structure,is attributed to the high electrical impedance of the structure due to its small capacitance and high electrical resistance.Finally,the surfaces of corroded samples are observed by scanning electron microscope(SEM).  相似文献   

10.
Zn1-xMgxO films have been grown on silicon at various substrate temperatures by pulsed laser deposition.The structural and photoluminescent properties of films as a function of substrate temperature have been studied.The optimized substrate temperature is 650℃.The x-ray diffraction spectra indicate that the films are highly C-axis oriented,and no phase separation is observed.The crystal grain size of the films is about 100nm as examined by atomic force microscopy.The cross-sectional transmission electron microscopy verified the C-axis orientation of the Zn1-xMgxO.Thesr films showed ultraviolet photoluminescence at room temperature.The near-band-edge emission peak of the Zn1-xMgxO film deposited at 600℃ has a blueshift (0.40eV) larger than that of the film deposited at 500℃ (0.33eV).The ratio of the near-band-edge to defect level peak intensity is as large as 159.  相似文献   

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