Analysis of By-Products of N2-SF6 Gas Mixtures Sparked under Inhomogenous Field Conditions

A vast data on formation of by-products due to arc and spark decomposition of SF6 is available in literature [1–10]. But experimental work relating to N2 - SF6 gas mixtures is limited. In view of increasing application of gas mixtures, it is essential to understand the nature of by-products formed in gas mixtures. Many recent studies have highlighted the advantages of using N2-SF6 gas mixtures as a replacement to SF6 gas for High Voltage application, with a view to reduce emission of SF6 gas into the atmosphere. Majority of these studies are aimed at determining the basic characteristics of N2-SF6 gas mixtures. However, this study attempts to understand the nature and quantum of different species formed in N2-SF6 mixtures in the presence of insulating spacers when sparked under inhomogeneous field conditions

P-n junction photocurrent modelling evaluation under optical and electrical excitation

Based upon the quasi-equilibrium approximation, the validity of p-n junction modelling, has been experimentally investigated under synchronous electrical and optical excitation of silicon photo-diodes. The devices had areas of 8.2 mm(2) and reverse bias saturation currents of the order of 10(-10) A. Their current-voltage (I-V) response was exploited experimentally both in the dark and under various illumination levels. The quoted values for the saturation current, the ideality factor, the series resistance and the reverse-bias photocurrent are investigated for the simulation of the I-V curves via the quasi-equilibrium model. In addition, the measured I-V data have been further analysed to estimate the produced photocurrent as a function of the applied bias (forward or reverse) under given illumination levels. Comparisons between the simulated curves and the experimental data allowed a detailed photocurrent modelling validation. The proposed approach could be useful towards studying other parameters of optically activated p-n junctions such as: the bias dependence of the minority carrier diffusion lengths and/or the generated rates of electron-hole pairs (EHP)

Electrostatic repulsion between highly injecting metals: An experimental investigation

This paper is an experimental investigation of the major implications brought in the crossing resistance of mechanically contacted metals when operating in the high electronic injection regime, i.e., steady state interfacial voltage values greater than the max. acceptable level determined by specifications and less than the melting voltage. Under such operating conditions, monolayers of positive ions may be formed within interfacial cavities filled by the material from the surrounding space. The dominating ion neutralization process on the cathode controls the formation of “Helmholtz” inner layers at the metal cathode+oxide+gas interface. The presence of a positive ion monolayer over the cathode electrode will tend to reduce the field threshold required for electronic field emission and affect the overall currentvoltage characteristics