Gady Golan

Holon Institute of Technology, Cholon, Tel Aviv, Israel

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Publications (13)8.82 Total impact

  • Alexander Axelevitch, Gady Golan
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    ABSTRACT: Metal nanodimension structures have multiple applications in modern technology. Noncontinuous thin island metal films of several types of metals deposited on dielectric or semiconductor surface introduce a unique behavior. In response to light exposure in certain range, the metal islands present a resonant absorption of light accompanied with a collective behavior of free electrons in these islands. In this paper, we present one of the possible ways to increase the efficiency of solar cells with metal islands imbedded in a semiconductor junction. Rough calculation was performed for a silicon solar cell and showed an increase of 17.5% in the overall efficiency of the cell.
    Journal of Solar Energy. 06/2013; 2013.
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    ABSTRACT: Localized surface plasmons-polaritons represent collective behavior of free electrons confined to metal particles. This effect may be used for enhancing efficiency of solar cells and for other opto-electronic applications. Plasmon resonance strongly affects optical properties of ultra-thin, island-like, metal films. In the present work, the Finite Difference Time Domain (FDTD) method is used to model transmittance spectra of thin gold island films grown on a glass substrate. The FDTD calculations were performed for island structure, corresponding to the Volmer-Weber model of thin film growth. The proposed simulation model is based on fitting of experimental data on nanostructure of ultra-thin gold films, reported in several independent studies, to the FDTD simulation setup. The results of FDTD modeling are then compared to the experimentally measured transmittance spectra of prepared thin gold films and found to be in a good agreement with experimental data.
    Optics Express 02/2013; 21(4):4126-4138. · 3.55 Impact Factor
  • Microelectronics Reliability. 01/2011; 51:2119-2123.
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    ABSTRACT: — Segmentation is one of the fundamental issues in the field of image processing and computer vision. Various approaches include differentiating an object in the image as a final goal or for further processing (medical diagnosis, surveillance, 3-D reconstruction and more). Snakes, a model proposed by Kass, Witkin, and Terzopoulos in 1987, provides an efficient method for segmenting an object through the minimization of its energy. The advantage of snakes is in its ability to use high-level data given by the algorithm operator, as opposed to other methods such as the Laplace technique. The snakes model inherently imposes strong constraints on a given image in order to successfully segment an object. In this paper, the use of adjustment methods is described, which allow us to generalize the snake model to a wider range of applications. Through the use of pre-processing techniques, the model's constraints were softened. The main theoretical model and its use in facing a real life image is presented.
    Journal of The Society for Information Display - J SOC INF DISP. 01/2010; 18(3).
  • Gady Golan, Alex Axelevitch
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    ABSTRACT: Direct conversion of solar energy into electricity using the photovoltaic effect suffers of low efficiency. Thus, increasing the efficiency conversion becomes the major goal of solar cells manufacturers. One way to increase efficiency is by applying intrinsic semiconductor widening layer in the depletion zone of a P-N junction. P-I-N based Photovoltaic structures on single-crystalline silicon were built using “Sheet Plasma” sputtering method. Intrinsic silicon films and indium oxide films were grown in series on a [111] conventional p-type silicon wafer. Optical and electrical properties of the deposited films were investigated using laboratory equipment. It was found that the bandgap of the intrinsic silicon layer equals to 1.3 eV and the bandgap of the emitter layer (In2O3) equals to 3.04 eV. Resistivity of the obtained emitter layer was equal to 5.24·10−3 Ω·cm. Efficiency of the photovoltaic structures was no more than 2 %. This paper proves feasibility of growing photovoltaic devices using Sheet Plasma sputtering methods.
    Power Generation, Transmission, Distribution and Energy Conversion (MedPower 2010), 7th Mediterranean Conference and Exhibition on; 01/2010
  • Alex Axelevitch, Gady Golan
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    ABSTRACT: Light depended resistors (LDR) or photoresistors are semiconductor devices that are changing resistance under illumination. These devices have many applications in industrial controls: item counters, presence and proximity sensors, flame detectors, photometric devices, etc. If the light falling on the device has energy which is greater than the bandgap of the semiconductor, photons absorbed by the semiconductor excite electron–hole pairs which result in lowering the resistance of the semiconductor. Generally, these devices are made of semiconductors such as CdS or CdSe using a thin film technology, since they have traps and misfits in their atomic structure, leading to high dark current and noise.In this work, we describe a novel approach for a novel family of high sensitive light detectors made of single-crystalline silicon. Basic sensor was built in a flat shape providing lateral electrical transport of excited charged carriers. Simple laboratory methods were used to diffuse impurities on both sides of the sensor. The sample shows high sensitivity due to light intensity variation from dark to strong light (∼96,000lx). A 30 times variation in the sample resistance was obtained.
    Microelectronics Journal. 01/2009; 40:435-438.
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    ABSTRACT: In this work we present first results on the synthesis of vanadium oxide semi-transparent conducting thin films of p- and n-types. The films were deposited by thermal evaporation method in vacuum, on: silicon, glass, sapphire, and gold substrates. Temperature of substrate during deposition was set around 250 °C. As deposited films were of a p-type of conductivity. Thermal annealing at 420 °C of as-deposited films in air at atmospheric pressure resulted in a change in the conductivity type.Optical, electrical and thermal properties of the deposited films were studied. The topography of the films was studied using AFM microscope. P–N structures were created using VOx films on silicon and glass substrates. Electrical measurements had shown a non-linear behaviour of the samples.
    Thin Solid Films 10/2007; 515(24):8446-8449. · 1.87 Impact Factor
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    ABSTRACT: Electrical, optical, and mechanical properties of thin films significantly differ from those of bulk materials. Therefore, characterization methods for evaluation of thin film properties became highly important. A novel approach to the well known “Hot-Probe” method is proposed and applied in our work. The conventional Hot Probe characterization method enables only the definition of a semiconductor type, P or N, by identifying the majority charged carriers. According to the new Hot Probe technique, one can measure and calculate the majority charged carriers concentration and its dynamic parameters. Feasibility proof of the upgraded Hot Probe method was done in Si and Ge bulk, and in thin film semiconductor samples.
    Microelectronics Journal. 01/2006; 37:910-915.
  • Gady Golan, Alex Axelevitch
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    ABSTRACT: Vacuum photothermal processing (VPP) is the follower of rapid thermal processing (RTP) in thin film technologies. It is clear now that simultaneous action of high energetic photons (more than 1.5 eV) and electron beam, significantly affect surfaces of thin film systems. Furthermore, the interfaces between metal contacts and semiconductors (Si, Ge) undergone this simultaneous influence, tend to vary their electronic properties. The novel VPP method decreases surface and interface roughness in metal–semiconductor contacts. The electrons flow while VPP may be controlled using a special tungsten grid attached to a DC voltage. This control in the electrons flow enables a smooth variation of the potential barrier amplitude within the metal–semiconductor contacts.VPP experiments were done for following metal–semiconductors systems: Au, Ag, Al, Ti, Ni, In, Cu, V in contact with Si. The obtained results clearly indicate on a broad application range of the VPP process in semiconductors and in the thin film industry.
    Microelectronics Journal. 01/2006;
  • S. Eliahou-Niv, R. Dahan, Gady Golan
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    ABSTRACT: In this paper, an improved design of a tunable optical filter device which is driven by a piezoelectric actuator is proposed. The device can be used either as a tunable optical filter for discrete wavelength alignment or as a dynamic optical filter. The tunable filter is electrostatically driven and consists of three main parts: The electromechanical stage, the suspension and the thin film optical filter. The electromechanical stage and the suspension were designed using graph presentation methods, studied numerically using the finite element method (FEM). The thin film optical filter was designed by a thin film design software. The electromechanical stage was integrated with the suspension and tested as an angular driver of thin-film tilt interference filter for dense-wavelength division demultiplexing system applications.
    Microelectronics Journal. 01/2006; 37:302-307.
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    ABSTRACT: A novel system of integrated thin-film heater with an embedded thermocouple was developed. Thin-film metallic heaters are widely used today in various fields of electronics and microelectronics applications. The main goal of the heater is usually to maintain the temperature in the heated zone. A deterministic method to manufacture an in situ heater––thermocouple system, with a pre-determined heater resistance, to give a required heat power, was developed. In order to examine this novel method, thin-film heaters were made using layers of Al and NiCr alloys. The temperature of the thin-film heater was measured while heating by an embedded thin-film thermocouple, positioned in the vicinity of the heater. This thin-film thermocouple system consisted of Ni–Ag alloy. A precise control of the growing heater film, while deposition, became possible using a simultaneous measurement of the heater sample resistance.
    Microelectronics Reliability 01/2003; 43:509-512. · 1.14 Impact Factor
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    ABSTRACT: This paper concerns with integrated microscopic investigations of bipolar junction damages in silicon detectors following neutron irradiation. This phenomenon was studied by means of an advanced contact potential difference method in atomic force microscopy (AFM). The obtained results were confirmed by topographical investigations also done by AFM and electron beam induced current, installed on a conventional scanning electron microscope. The most detailed structural investigations were carried out by means of scanning tunnel microscope. It was found that in the interval of neutron fluences, Φ,9.9×1010⩽Φ⩽3.12×1015 n/cm2 the damage to the silicon lattice structure is accumulative, from small point defects to high defect accumulations. These defects consisted of large complexes of dislocation loops and vacancies, however, in the p–n junction region, only vacancies remained. This deterioration in the junction crystalline structure, resulted in a population inversion of the free charge carriers, from n- to p-type. The novelty of this research consists of the direct correlation, found between the structural defects and the mechanical and electrical properties of the diode junction.
    Microelectronics Reliability 01/2001; 41:67-72. · 1.14 Impact Factor
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    ABSTRACT: The influence of electron beam during vacuum photo-thermal processing (VPP) treatment of metal–silicon contacts, was studied. This is the first experimentally evidence for a novel effect of potential barrier variations in metal-semiconductor contacts following a VPP. The possibility to control the potential barrier in metal–silicon contacts was shown. The same nature of influence of electron beam on the potential barrier between silicon and other metals such as: Ti and Ni were presented as well. The potential barriers in: Ti–Si and Ni–Si were varied from 0.605 to 0.785 eV and from 0.571 to 0.672 eV, respectively. Furthermore, it was found experimentally that the metallic surface order in the metal-silicon pair, following VPP, was dramatically improved. Surface roughness was decreased and the electrical conductivity was increased. Finally, the influence of a non-coherent irradiation on the properties of metal-silicon contacts was studied.
    Microelectronics Reliability 01/2001; 41:871-879. · 1.14 Impact Factor