Space Charge Limited Current Measurements Research Articles

Study of localized states in FEP by space charge limited current measurements

The measurement of ohmic and space charge limited current at different temperatures in fluorinated ethylene propylene (FEP) of 250 μm thickness is reported. The current-voltage characteristics follow the theoretically proposed models for the mechanism of conduction in the thin insulating films. The experimental results have been analysed on the basis of the existing knowledge and a few important parameters related with the transport mechanism in FEP have been evaluated. Two temperature-induced changes in the activation energy E for conduction have been observed. For T <413K, E⋍0.2 eV ; for 413< T <458K, E⋍0.5 eV . and for T >458K, E⋍0.99 eV . It is observed that the specimen is extrinsic over all the temperature ranges. From these findings the density of states in the conduction band, the depth of Fermi level from the conduction band, the statistically important energy levels and their densities of states have been determined. The presence of discrete electron levels at depths 0.2 eV, 0.5 eV and 0.99 eV below the conduction band having densities of states 2.8 × 10 22, 1 × 10 19 and 4.6 × 10 12 respectively have been determined which are dominant over the three temperature regions. Energy band diagram for FEP is plotted.

Space charge limited current measurements in ZnIn2S4

Space charge limited current measurements in ZnIn2S4 and some ZnIn2S4In2S3 alloys are made. A continuous trap distribution which can be quite accurately described by an exponential model is a distinctive characteristic of all experimental data. The “energy decay constant” of the distribution is about 50 meV, which agrees with the conclusion obtainable by other types of measurements. Raumladungsbegrenzte Strome wurden in ZnIn2S4 und in einigen ZnIn2S4In2S3 Legierungen gemessen. Eine stetige, von einem Exponentialmodell genau beschriebene „Trap”- Verteilung ist fur die experimentellen Ergebnisse kennzeichnend. Die „Abfallkonstante” der Exponentialverteilung betragt ungefahr 50 meV, was mit den Ergebnissen anderer Mesverfahren ubereinstimmt.

On the difficulty of determining surface lifetimes from pulsed space charge limited current measurements

On the difficulty of determining surface lifetimes from pulsed space charge limited current measurements