Electrical Properties of Poly-N-Epoxypropylcarbazole/Vanadium Pentoxide Composite

In the present work the electrical properties of poly-N-epoxypropylcarbazole (PEPC) and vanadium pentoxide (V2O5) composite have been studied. The composite was formed by mixing of PEPC solution in benzene with V2O5 powder and stirring at room temperature. The composite solution was deposited on a dielectric substrate with copper electrodes and the Cu/PEPC-V2O5/Cu surface type film samples were fabricated. The Cu/V2O5/Cu samples were used as a reference where the films were deposited from the mixture of V2O5 powder in distilled water. Resistance-temperature relationship and voltage-current characteristics of the composite and V2O5 samples were studied by using conventional digital voltmeter and ammeter in the temperature range of 27-110 °C with an error of ±0.5%. It was observed that the DC electrical conductivity, activation energy and non-linearity of voltage-current characteristics of the samples are temperature dependent. It was found that the temperature dependence of electrical conductivity of the V2O5 samples on the whole obeys T-1/4 law whereas the PEPC-V2O5 ones show visible deviations from that. The PEPC-V2O5 samples may be used as thermistors as the temperature coefficient of their resistance is large and at 27 °C is equal to -4.7%/°C

The Photo-Electrical Behavior of n-Si and p-Si/Orange Dye/ Conductive Glass Cells

The photo-electrical behavior of n-Si/orange dye/conductive glass and p-Si/orange dye/conductive glass sandwich type cells were investigated. In these cells crystal silicon of n-type and p-type and conductive glass (CG) electrodes were employed and the aqueous solution of organic dye (OD) was used as an electrolyte in the distilled water. Under filament lamp illumination, photo-induced open-circuit voltage and shortcircuit current exponentially dropped with time for the n-Si/orange dye/CG cell. In the p-Si/orange dye/CG cell, the photovoltaic effect was not observed. The n-Si/OD/CG cell showed high photo-electrical response under illumination. In the light-voltage/current conversion, these cells behaved as a differentiator and exhibited charge-storage properties

Effect of Temperature and Humidity on Electrical Properties of Organic Orange Dye Complex Films

In this study the effect of temperature and humidity on electrical properties of organic orange dye (OD) complex with vinyl-ethynyl-trimethyl-piperidole (VETP) have been examined. Thin films of OD (C17H17N5O2) and VETP (C12H19NO) complex were deposited from 10 wt.% (5 wt.% of each matter) solution in mixture of distilled water (80%) and spirit. The films were grown at room temperature under normal gravity conditions, i.e., 1 g and in a spin coater at an angular speed of 300 RPM. The Cu/OD-VETP/Cu surface type samples were fabricated and their low frequency (10 Hz) AC electric characteristics were evaluated for the temperature range 30-95 °C at ambient humidity of 45-80%. It was observed that at normal conditions the conductivity of the samples is temperature dependent and shows semi-conductive behavior with activation energy of 0.55 eV. It was found that with increase in humidity the resistance of the samples decreases and at humidity values equal to 60-70% the irreversible transition from semi-conductive to conductive state takes place. It is supposed that in the former state the conductive matrix is formed due to incorporation of the water molecules into OD-VETP complex

Enhancement of X-ray emission in the side on direction in a Mather-type plasma focus

A 1.8 kJ Mather-type plasma focus (PF) for argon and hydrogen filling is examined. Two anode configurations are used. One is tapered towards the anode face, and the other is cylindrical but the face is cut at different angles. At optimum conditions, the system is found to emit Cu–Kα X-rays of about 1.6±0.1 J/sr in the side-on direction for argon filling, which is about 32% of the total X-ray emission. In 4π-geometry, maximum total X-ray yield and wall plug efficiency found are 26.4±1.3 J and 1.5± 0.1% respectively. The modified geometry may help to use the PF as a radiation source for X-ray diffraction

Deposition of titanium nitride on AISI-304 in a plasma focus environment

Polycrystalline, smooth, and hard thin films of TiN are successfully deposited on AISI-304 substrates using a 1.5 kJ Mather-type dense plasma focus device charged at 18 kV. The purpose of this study is to investigate the structural and mechanical properties of the TiN thin films in terms of ion dose and substrate position to establish the optimum deposition conditions. The films are analyzed using XRD, SEM, electron microprobe and micro-hardness testing. XRD confirms the deposition of a polycrystalline TiN thin film together with the emergence of an iron chromium nickel phase. The surface hardness-in comparison to the unexposed substrate-is found to increase up to 250% when a film is deposited using 30 focus shots at an axial distance of 6 cm. SEM micrographs show that the quality of the film is improved with an increasing number of focus shots. The constituent elements of the film are also confirmed by electron microprobe

Spectroscopic optimization of abnormal glow conditions for plasma ion nitriding

Optical emission spectroscopy is used to characterize the production of active species as a function of hydrogen concentration in the mixture under different operating conditions. A major concern is to enhance the concentration of the active species by hydrogen addition that carry several electron volts energy above their ground states, and thus affect the surface chemistry. The emission intensity of the selected optical transitions of molecular and atomic species is measured to determine the functional dependence of their radiative states. The relative ground state molecular ion density [N2+] is measured from the emission intensity of the first negative band head (λ = 391.4 nm, 0–0) by considering the fact that in low temperature plasma, ion with single charge is produced by the electron impact, and the ion density is proportional to the electron density. It is found that the concentration of the active species may be enhanced significantly by selecting an appropriate gas composition and operating parameters. The SS-304 samples are nitrided under the optimum conditions for 4, 8, 12 and 16 hours and hardness values are found to increase five times for 16 hours treatment time. The optimized discharge conditions are found favorable for plasma ion nitriding

Mode transition in magnetic pole enhanced inductively coupled argon plasmas

The electrical probe (Langmuir probe) diagnostics of different plasma parameters and operation regimes (E/H modes) of magnetic pole enhanced, inductively coupled (MaPE-ICP) argon plasmas are investigated. It is shown that uniform, high density (ne ~ 1012 cm-3) and low electron temperature (Te ~ 1.5 eV) plasma can be produced in low pressure argon discharges at a low power (100 W). It is found that an MaPE-ICP reactor operates in two different modes; capacitive (E mode) and inductive (H mode). No density jump or hysteresis are reported between these modes. The effect of pressure on transition power, where the mode changes from E to H mode at 20 sccm gas flow rate are studied and it is found that for all pressures tested (~ 7.5 mTorr to 75 mTorr) the transition power remains same. In the inductive mode, the above plasma parameters show a smooth variation with increasing filling gas pressure at fixed power. The intensity of the emission line at 750.4 nm due to 2p1 → 1s2 (Paschen’s notation) transition, closely follows the variation of ne with RF power and filling gas pressure. Measured electron energy probability function (EEPF) shows that electron occupation mostly changes in the high-energy tail, which enlightens close similarity of the 750.4 nm argon line to electron number density (ne). The behaviour of the electron energy probability function (EEPF) with regard to pressure and RF power in two operational modes is presented