Stanko Ostojic

Analytical model of a Si TFT with cylindrical source and drain

In this paper a new analytical model of a silicon thin film transistor (Si TFT) with cylindrical source and drain, is presented. In first part of the text, some basic TFT characteristics and possible applications are exposed. Analytical model is developed starting from Poissons equation, and current density dependence on electric field and voltage. Development of conductivity model follows and finally current-voltage characteristics model. Improvement of the I-V characteristics model is achieved by developing carrier mobility model which is incorporate in it.

Surrounding gate long channel nanowire MOSFET modelling—extended analysis

Based on the approximate solution of Poisson?s equation in the case of a p-doped silicon body, an improved current-voltage characteristic model of long-channel cylindrical surrounding-gate Si nanowire MOSFET is proposed. The improvement itself considers a realistic description of the carriers? mobility degradation owing to the radial electric field and a more detailed and accurate analytical solution to the 1D Poisson?s equation than the solutions available in the literature. The model is valid in the wide range of the doping concentration and shows a satisfactory level of agreement with the two-dimensional simulation results and the former models. It can also be applied to different operation regimes such as subthreshold, linear and saturation regimes.

The interpretation of the intensity of components of laser scattering by interaction with matter

The measurement of scattered light properties offers many optical, acoustic, dielectric, thermodynamic data about the scattering medium. Brillouin spectroscopy with various modifications and different laser types has been a measurement technique in acoustics for a long time, but it is still important as an autonomous technique. It enables more detailed and exhaustive knowledge of the acoustic and optical properties of matter. A series of Rayleigh–Brillouin spectra are recorded for a set of organic solvents and phytol. The equipment used in spectra recordings enables the measurement of four components of scattered laser intensity Ihh, Ihv, Ivv and Ivh. The ratios of the linewidth, as well as shifts, are determined for Rayleigh–Brillouin spectra. According to them, the hypersound velocity and absorption coefficients can be calculated. There is much software for data processing obtained in laser interaction with matter, with different programming tools. An analysis of spectra is performed, i.e. an examination of which distribution (Gaussian or Lorentzian) better explains the experimentally obtained diagrams.

Diffraction effects, scattering effects, analytical problems, numerical algorithms, and program packages

Diffraction problems in analytical treatments and numeric have been constant topics for a very long time and there are a lot of different analytical expressions as well as numerical algorithms. The modern approaches are concentrated in the area of particle sizing, fiber optical sizing and loss evaluation in laser physics and techniques. Some problems between the fiber optics dimensioning and particles of cylindrical shape dimensioning are chosen and based on literature; some ameliorations in numerical approaches are made. The evolved expressions can be used for different laser wavelengths, different dimensions of disturbance objects (in scattering and diffraction phenomena) as well as different indices of refractions where the particles (in a very general way) are stratified. Some existing programs for scattering are discussed and the new computer architecture is presented here.