Deposition And Surface Modification Of Low-K Thin Films For Ild Application In Ulsi Circuits

The low-k thin films have been deposited successfully by sol gel technique using tetraethylorthosilicate (TEOS) precursor and the surface of deposited thin films have been modified by wet chemical treatment using trimethylcholorsilane (TMCS) and hexane solution with 15 % volume ratio to remove the hydroxyl groups from the surface of deposited low-k thin films. The characterization of the as deposited and surface modified low-k thin films has been carried out by Ellipsometer, Fourier transform infrared (FTIR) spectrometer, and contact angle meter. For the determination of the dielectric constant of the deposited thin film the metal –insulator-semiconductor (MIS) structure was formed by depositing the Aluminium (Al) metal on the low-k thin film. Further the capacitance-voltage curve of the MIS structure has been obtained at 1 MHz frequency. The dielectric constant of the as deposited thin film is found to be 2.15. The lowering of O-H peaks and appearance of CH3 peaks in FTIR spectra confirms the surface modification of SiO2 films. The contact angle of the deposited thin film is changed from 83.3° to 104° after surface modification that validates the transformation of thin film surface from hydrophilic to hydrophobic after the surface modification treatment. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/950

Wave attenuation to clock sojourn times

The subject of time in quantum mechanics is of perennial interest especially because there is no observable for the time taken by a particle to transmit (or reflect) from a particular region. Several methods have been proposed based on scattering phase shifts and using different quantum clocks, where the time taken is clocked by some external input or indirectly from the phase of the scattering amplitudes. In this work we give a general method for calculating conditional sojourn times based on wave attenuation. In this approach clock mechanism does not couple to the Hamiltonian of the system. For simplicity, specific case of a delta dimer is considered in detail. Our analysis re-affirms recent results based on correcting quantum clocks using optical potential methods, albeit in a much simpler way.Comment: 4 pages, 5 figures. Minor corrections made and journal reference adde

Dephasing via stochastic absorption: A case study in Aharonov-Bohm oscillations

The Aharonov-Bohm ring has been the mainstay of mesoscopic physics research since its inception. In this paper we have dwelt on the problem of dephasing of AB oscillations using a phenomenological model based on stochastic absorption. To calculate the conductance in the presence of inelastic scattering we have used the method due to Brouwer and Beenakker. We have shown that conductance is symmetric under flux reversal and visibility of AB oscillations decay to zero as a function of the incoherence parameter thus signalling dephasing in the system. Some comments are made on the relative merits of stochastic absorption with respect to optical potential model, which have been used to mimic dephasing.Comment: 4 pages, 4 figures Minor corrections made and journal reference adde

Hartman effect in presence of Aharanov Bohm flux

The Hartman effect for the tunneling particle implies the independence of group delay time on the opaque barrier width, with superluminal velocities as a consequence. This effect is further examined on a quantum ring geometry in the presence of Aharonov-Bohm flux. We show that while tunneling through an opaque barrier the group delay time for given incident energy becomes independent of the barrier thickness as well as the magnitude of the flux. The Hartman effect is thereby extended beyond one dimension and in the presence of Aharonov-Bohm flux.Comment: 4 pages, 4 figure

Distribution of Wigner delay time from single channel disordered systems

We consider the scattering of an electron from a semi-infinite one-dimensional random medium. The random medium is characterized by force, -\d V/\d L being the basic random variable. We obtain an analytical expression for the stationary delay time ($\tau$) distribution $P_s(\tau)$ within a random phase approximation. Our result agrees with earlier analytical expressions, where the random potential is taken to be of different kind, indicating universality of the delay time distribution, i.e., delay time distribution is independent of the nature of disorder.Comment: 8 pages RevTeX, no figure

In-field entanglement distribution over a 96 km-long submarine optical fibre

Techniques for the distribution of quantum-secured cryptographic keys have reached a level of maturity allowing them to be implemented in all kinds of environments, away from any form of laboratory infrastructure. Here, we detail the distribution of entanglement between Malta and Sicily over a 96 km-long submarine telecommunications optical fibre cable. We used this standard telecommunications fibre as a quantum channel to distribute polarisation-entangled photons and were able to observe around 257 photon pairs per second, with a polarisation visibility above 90%. Our experiment demonstrates the feasibility of using deployed submarine telecommunications optical fibres as long-distance quantum channels for polarisation-entangled photons. This opens up a plethora of possibilities for future experiments and technological applications using existing infrastructure.Comment: 6 pages, 4 figure

Newtonian Analysis of Gravitational Waves from Naked Singularity

Spherical dust collapse generally forms a shell focusing naked singularity at the symmetric center. This naked singularity is massless. Further the Newtonian gravitational potential and speed of the dust fluid elements are everywhere much smaller than unity until the central shell focusing naked singularity formation if an appropriate initial condition is set up. Although such a situation is highly relativistic, the analysis by the Newtonian approximation scheme is available even in the vicinity of the space-time singularity. This remarkable feature makes the analysis of such singularity formation very easy. We investigate non-spherical even-parity matter perturbations in this scheme by complementary using numerical and semi-analytical approaches, and estimate linear gravitational waves generated in the neighborhood of the naked singularity by the quadrupole formula. The result shows good agreement with the relativistic perturbation analysis recently performed by Iguchi et al. The energy flux of the gravitational waves is finite but the space-time curvature carried by them diverges.Comment: 23 pages, 8 figure

Profiles of emission lines generated by rings orbiting braneworld Kerr black holes

In the framework of the braneworld models, rotating black holes can be described by the Kerr metric with a tidal charge representing the influence of the non-local gravitational (tidal) effects of the bulk space Weyl tensor onto the black hole spacetime. We study the influence of the tidal charge onto profiled spectral lines generated by radiating tori orbiting in vicinity of a rotating black hole. We show that with lowering the negative tidal charge of the black hole, the profiled line becomes to be flatter and wider keeping their standard character with flux stronger at the blue edge of the profiled line. The extension of the line grows with radius falling and inclination angle growing. With growing inclination angle a small hump appears in the profiled lines due to the strong lensing effect of photons coming from regions behind the black hole. For positive tidal charge ($b>0$) and high inclination angles two small humps appear in the profiled lines close to the red and blue edge of the lines due to the strong lensing effect. We can conclude that for all values of $b$, the strongest effect on the profiled lines shape (extension) is caused by the changes of the inclination angle.Comment: Accepted by General Relativity and Gravitatio

Statistical properties of phases and delay times of the one-dimensional Anderson model with one open channel

We study the distribution of phases and of Wigner delay times for a one-dimensional Anderson model with one open channel. Our approach, based on classical Hamiltonian maps, allows us an analytical treatment. We find that the distribution of phases depends drastically on the parameter $\sigma_A = \sigma/sin k$ where $\sigma^2$ is the variance of the disorder distribution and $k$ the wavevector. It undergoes a transition from uniformity to singular behaviour as $\sigma_A$ increases. The distribution of delay times shows universal power law tails $~ 1/\tau^2$, while the short time behaviour is $\sigma_A$- dependent.Comment: 4 pages, 2 figures, Submitted to PR

Naked Singularity Formation In f(R) Gravity

We study the gravitational collapse of a star with barotropic equation of state $p=w\rho$ in the context of $f({\mathcal R})$ theories of gravity. Utilizing the metric formalism, we rewrite the field equations as those of Brans-Dicke theory with vanishing coupling parameter. By choosing the functionality of Ricci scalar as $f({\mathcal R})=\alpha{\mathcal R}^{m}$, we show that for an appropriate initial value of the energy density, if $\alpha$ and $m$ satisfy certain conditions, the resulting singularity would be naked, violating the cosmic censorship conjecture. These conditions are the ratio of the mass function to the area radius of the collapsing ball, negativity of the effective pressure, and the time behavior of the Kretschmann scalar. Also, as long as parameter $\alpha$ obeys certain conditions, the satisfaction of the weak energy condition is guaranteed by the collapsing configuration.Comment: 15 pages, 4 figures, to appear in GR