Sharif Digital Repository

In this research, nickel thin films have been deposited on Si (1 0 0) substrate using the dc sputtering method. Then, the deposited layers were annealed in different temperatures to oxidize and crystallize the as prepared layers. Scanning electron microscopy (SEM) analysis indicated that the nanorod shape of the nickel oxides has grown on the substrate and x-ray photoelectron spectroscopy determined the formation of stoichiometric NiO on the surface. Field emission (FE) measurements of the NiO nanorods exhibited the lowest turn-on electric field at about 3.8 V μm-1 in the 300 μm vacuum gap. Moreover, the field enhancement factor (β) was measured of about 4109 for this sample. The FE... 

The effect of etching time scale of glass surface on its statistical properties has been studied using atomic force microscopy technique. We have characterized the complexity of the height fluctuation of an etched surface by the stochastic parameters such as intermittency exponents, roughness, roughness exponents, drift and diffusion coefficients and found their widths in terms of the etching time. © 2006 Elsevier B.V. All rights reserved  

We study (2+1)-dimensional single step model for crystal growth including both deposition and evaporation processes parametrized by a single control parameter p. Using extensive numerical simulations with a relatively high statistics, we estimate various interface exponents such as roughness, growth and dynamic exponents as well as various geometric and distribution exponents of height clusters and their boundaries (or iso-height lines) as function of p. We find that, in contrary to the general belief, there exists a critical value at which the model undergoes a roughening transition from a rough phase with in the Kardar-Parisi-Zhang universality to a smooth phase with , asymptotically in... 

A very simple and well-controlled procedure was employed to prepare CdS nanoparticle/few-layer MoS2 nanosheet/Indium tin oxide (ITO) thin film heterostructures. To tune and fabricate the CdS/MoS2(t)/ITO thin films with various surface topographies, first electrophoretic deposition (EPD) was used to deposit MoS2 nanosheets on the ITO substrate under an optimized applied potential difference (8 V) for different deposition times (t) of 30, 60, 120 and 240 s. Then, CdS nanoparticles were deposited via a successive ion layer adsorption and reaction (SILAR) technique. The highest photo-current density of 285 μA cm-2 was measured for the CdS/MoS2(60 s)/ITO sample, which was about 2.3 times higher... 

Stochastic parameters of self-agglomerated metallic nanoparticles on a dielectric film surface were studied using atomic force microscopy (AFM) analysis. In this regard, the rough surfaces including the nanoparticles were analyzed and characterized using structure function, roughness exponent and power spectrum density of the AFM profiles and their gradients, for different metal concentrations and heat treatment temperatures. The diffusion parameters, such as activation energy, of the nanoparticles initially accumulated on the surface into a porous and aqueous silica thin film were obtained using the AFM spectral analysis of the profiles and their gradients. It was found that the tip... 

We have studied the stochastic parameters of surface iron oxide nanograin chains, 97 nm in diameter and 2.4 νm in length, prepared at different annealing temperatures, using atomic force microscopy (AFM) spectral analysis. In this regard, the roughness of the thin films including self-assembled twisted nanograin chains has been analysed and characterized using the height-height correlation function, the roughness exponent as well as the power spectrum density of the AFM profiles and their gradient, for the different annealing temperatures. The tip convolution effect on the stochastic parameters under study has also been investigated. The kinetics of the formation of nanograins on the film...