Papers by Keyword: Schottky Junction

Abstract: In this paper, near unity broadband absorption of Van der Waals semiconductors on a metallic substrate, and their photovoltaic performances in the visible spectrum are simulated. Ultrathin layered semiconductors such as Molybdenum disulfide (MoS₂), Tungsten disulfide (WS₂), Molybdenum di-selenide (MoSe₂), Tungsten di-selenide (WSe₂), Molybdenum ditelluride (MoTe₂), and Tungsten ditelluride (WTe₂) can create strong interference by damping optical mode in their multilayer form and increase light absorption at their heterojunctions with noble metals. From our simulation, it is observed that this absorbance can reach up to 94% when the semiconductors are placed on a gold substrate. The optimum thickness of these semiconductors in their heterostructures with gold is analyzed to create resonant absorption to generate the maximum amount of current density. The power conversion efficiency of the designed Schottky junction solar cells is calculated from their current density vs bias voltage characteristics that ranges from 1.57% to 6.80%. Moreover, the absorption coefficient, dark current characteristic, electric field intensity distribution in the device, and carrier generation rate during light illumination are presented with a view to characterizing and comparing among the parameters of TMDC based nanoscale solar cell.

Abstract: In this paper, we present the photovoltaic characteristics of nanoscale Schottky junction solar cell consisting of graphene and GaAs using numerical simulation based on non-equilibrium Green’s function formalism. In our model, light-matter interaction is formulated by the coupling and scattering self-energy matrices whereas heterostructure is designed with a Hamiltonian matrix. An efficiency of 2.36% is obtained for monolayer graphene on GaAs; the efficiency is later enhanced to 5.40% by increasing both the number of graphene layers and the doping concentration of GaAs. The parameters to calculate power conversion efficiency, series and shunt resistances are extracted from the J-V characteristic. The I-V characteristic is also numerically simulated to extract reverse saturation current, ideality factor, and rectification ratio. Moreover, the power density is calculated for the optimized structure; the maximum power density of 7.46 mW/cm² is obtained for four layers of graphene and a doping concentration of 10¹⁷/cm³ in GaAs.

Abstract: In this paper, we report on the performance of Ti/4H-SiC Schottky junctions, whereas the contact material is either e-beam evaporated or magnetron sputter deposited. When applying the first technique, the Schottky barrier height is lowered at room temperature by about 80 meV or by about 160 meV extracted from current/voltage and capacitance/voltage measurements, respectively. Furthermore, e-beam evaporation of the Ti contact results in an ideality factor closer to 1 when comparing structures of the same design.

Abstract: This article studies the effect of anode width of dual schottky magnetodiode to sensitivity. The width is varied at 5, 15 and 35 μm with the forward bias 0.2 mA and reverse bias 0.25 nA. The applied magnetic field is varied from -0.4 T - 0.4 T. The output response DI_D is the cathode current difference. The best relative sensitivity S_R is 54.6 mT^-1 in the case of reverse bias at W_A= 5 μm. The worst S_R is 26.9 mT^-1in the case of forward bias at W_A= 35 μm. It depends on the ratio of the distance of deviation current in Y direction (DY) to the width of anode W_A. It shows that the width W_A should be design as narrow as possible and the operating current should be kept as low as one can. The current density from simulation can explain the mechanism of the device.

Abstract: Thermoelectric cells and Solar cells are source of harvesting energy from heat and light respectively. In this study both are fabricated on a single cell using n-Si and p-Si single crystal strips.Later, temperature gradient cells are also fabricated . The fabricated Phtoto-thermoelectric cells and Temperature gradient celss are investigated, showing improvement in seebeck effect.

Abstract: Reported here is a new method of fabricating the graphene/silicon schottky junction. Using a femtosecond laser, graphene oxides are reduced to graphene and behave a metal. The junction of reduced GO and Si shows rectifying behavior indicating that the junction is schottky junction. Take advantage of the laser fabricating method, one can get reduced GO at any position on the substrate. Xps spectra shows that the reduced GO has only 12% oxygen content, and it is truly have a good conductivity similar to metal. This method opens a new effective way to graphene-based micro nano electronics.

Abstract: In this paper, the electricalcharacteristics of Ergermanideschottkyjunction werestudied for source / drain of n-typeschottky barrier Ge MOSFET.Ergermanideshowed the lowest ideality factor at RTP temperature of 600°C among the applied temperature range. When RTP temperature was increased, barrier height and work function of Ergermanidebecame similar to those of Er2Ge3. From the analysis of the leakage current, it is shown that the Poole-Frenkel barrier lowering was dominant at RTP 600°C and the influence of the Schottky barrier lowering was decreased as RTP temperature increased. The electrical characteristics of Ergermanideare very sensitive to the RTP temperature andclosely related tothe trapsites which are generated by germanidation.

Abstract: The reduction of reverse leakage currents was attempted to fabricate 4H-SiC diodes with large current capacity for high voltage applications. Firstly diodes with Schottky metal of titanium (Ti) with active areas of 2.6 mm2 were fabricated to investigate the mechanisms of reverse leakage currents. The reverse current of a Ti Schottky barrier diode (SBD) is well explained by the tunneling current through the Schottky barrier. Then, the effects of Schottky barrier height and electric field on the reverse currents were investigated. The high Schottky barrier metal of nickel (Ni) effectively reduced the reverse leakage current to 2 x 10-3 times that of the Ti SBD. The suppression of the electric field at the Schottky junction by applying a junction barrier Schottky (JBS) structure reduced the reverse leakage current to 10-2 times that of the Ni SBD. JBS structure with high Schottky barrier metal of Ni was applied to fabricate large chip-size SiC diodes and we achieved 30 A- and 75 A-diodes with low leakage current and high breakdown voltage of 4 kV.

Abstract: In this study, we report well performance of Dye Sensitized Solar Cell (DSSC) coated with copper (Cu) by using the electroplating method. The Cu nanoparticle was impregnated into the pore of the titanium dioxide (TiO2) thin film. Particle contact between Cu and TiO2 plays important role to reduce the recombination effect of the electron and also lead to increase the electron transport in DSSC cell. Here, we used natural dye extracted from black rice and carbon from black ink as counter electrode. It is found that efficiency of DSSC coated with Cu nanoparticle is higher than pure DSSC which is obtained from I-V characterization. It shows that efficiency of DSSC is about 0.019% without coating Cu and enhanced about 0.105% after coating Cu. The analysis of internal resistance of DSSC was measured from Electrochemical Impedance Spectroscopy (EIS) characterization.

Abstract: This paper presents the simulation model of Dual Magnetodiode and Dual Schottky Magnetodiode using Sentaurus TCAD to simulate the virtual structure of magneto device and apply Hall Effect to measure magnetic field response of the device. Firstly, we use the program to simulate the magnetodiode with p-type semiconductor and aluminum anode and measure electrical properties and magnetic field sensitivity. Simulation results show that sensitivity of Dual Schottky magnetodiode is higher than that of Dual magnetodiode.