Sharif Digital Repository

In this paper, we present a study on the contribution of silicon nanocrystals to the electrical transport characteristics of large (100 μm × 100 μm) and small (100 nm × 100 nm) metaloxide-semiconductor (MOS) capacitors at room temperature. A layer of silicon nanocrystals is synthesized within the oxide of these capacitors by ultra-low energy ion implantation and annealing. Several features including negative differential resistance (NDR), sharp current peaks and random telegraph signal (RTS) are demonstrated in the current-voltage and current-time characteristics of these capacitors. These features have been associated to charge storage in silicon nanocrystals and to the resulting Coulomb... 

This paper discusses the determination of the transition curves for a pair of spur gear with coulomb friction. Transition curves are the loci of periodic response of parametrically excited systems and separate the stable and unstable solutions. A discrete model of a pair of spur gear is developed and the friction forces are calculated base on instantaneous dynamic force between gear teeth. The dynamic equation of the system is a linear ordinary differential equation with periodic coefficients. Periodic friction torque, as the parametric excitation is represented by Fourier series. The loci of periodic solutions are determined in μ - Γ plane (coefficient of friction-contact ratio) by strained... 

The static Coulomb potential of Quantum Electrodynamics is calculated in the presence of a strong magnetic field by computing perturbatively the vacuum expectation value of the corresponding Wilson loop in the lowest Landau level (LLL) approximation. In the LLL, two different regimes of dynamical mass, md yn., can be distinguished. These two regimes are |q2 | ≪ m2 d yn. ≪ |eB| and m2 d yn. ≪ |q2 | ≪ |eB|, where q is the longitudinal components of the momentum relative to the external magnetic field B. As it turns out, the potential in the first regime, |q2 | ≪ m2 d yn. ≪ |eB|, has the general form of a modfied Coulomb potential V1(R, θ ) = −α R A1(α, θ ) −γ A2 R (α 2 ,θ ) + γ 2 A3 (α,θ ) ,... 

In this paper, we have studied the effect of annealing under slightly oxidizing ambient (N2 + O2) on the structural and electrical characteristics of a limited number of silicon nanoparticles embedded in an ultra-thin SiO2 layer. These nanoparticles were synthesized by ultra-low energy (1 keV) ion implantation and annealing. Material characterization techniques including transmission electron microscopy (TEM), Fresnel imaging and spatially resolved electron energy loss spectroscopy (EELS) have been used to evaluate the effects of oxidation on structural characteristics of nanocrystal layer. Electrical transport characteristics have been measured on less than one hundred nanoparticles by... 

In this paper, we present a study on the contribution of silicon nanocrystals to the electrical transport characteristics of large (100 μm × 100 μm) and small (100 nm × 100 nm) metal-oxide-semiconductor (MOS) capacitors at room temperature. A layer of silicon nanocrystals is synthesized within the oxide of these capacitors by ultra-low energy ion implantation and annealing. Several features including negative differential resistance (NDR), sharp current peaks and random telegraph signal (RTS) are demonstrated in the current-voltage and current-time characteristics of these capacitors. These features have been associated to charge storage in silicon nanocrystals and to the resulting Coulomb... 

In this article, we present the room-temperature current-voltage characteristics of a nanometer scale (100×100 nm2) metal-oxide-semiconductor capacitor containing few (less than 100) silicon nanoparticles. The layer of silicon nanoparticles is synthesized within the oxide of this capacitor by ultra low-energy ion implantation and annealing. Current fluctuations in the form of discrete current steps and sharp peaks appeared in the static and dynamic I (V) characteristics of the capacitor. These features have been associated to quantized charging and discharging of the nanoparticles and the resulting Coulomb interaction to the tunneling current. © 2005 American Institute of Physics  

In this paper, we present a study on the contribution of silicon nanocrystals to the electrical transport characteristics of large (100 µ x 100 µm) and small (100 nm x 100 nm) metaloxide- semiconductor (MOS) capacitors at room temperature. A layer of silicon nanocrystals is synthesized within the oxide of these capacitors by ultra-low energy ion implantation and annealing. Several features including negative differential resistance (NDR), sharp current peaks and random telegraph signal (RTS) are demonstrated in the current-voltage and current-time characteristics of these capacitors. These features have been associated to charge storage in silicon nanocrystals and to the resulting Coulomb...