Experimental evidences are presented on the light-induced changes in the transport properties of amorphous As2Se3 thin films evaporated onto substrates held close to the glass-transition temperature. The transient hole-photocurrent before and after He-Ne laser irradiation has been studied as functions of temperature and applied electric field. We found that the laser irradiation increases the transit times for hole and changes the temperature dependence of dispersion parameters. These changes can be removed by annealing and accompany the photodarkening characteristic of photostructural transformation. The simulation study of transient photocurrent shows that the temperature dependence of the dispersion parameters for the irradiated films can be explained by an increase in the width of the Gaussian distribution of the gap state. We conclude that the phenomena are due to the variation in the gap-state structure arising from photostructural transformation.

View full abstract

There are two kinds of exposuring method on laser beam printer ; background area exposuring (BAE), and image area exposuring (IAE). The former makes laser beam exposuring on the area outside the image dot, and it has a merit to use ordinary electrophotographic processing. The latter makes exposuring on the region of blacken areas, and it must be used by reversal development.
In this paper, we have analized these methods both by computer simulations and experiments, on the aspect of reproduction of lines and characters, then we have obtained some results for optimization of laser spot diameter.

View full abstract

The electrical and dielectrical properties of the organic layered photoreceptors were studied from Fourier transform of the transient currents by applying small step voltage. It was shown that the information about carrier injection at CGL-CTL and substrate-CGL interfaces was obtained in dielectric spectra of low frequency region in addition to the dipole orientation of the binder polymer. The present D. C. transient measurment was found to be also useful for studying the energy matching at the interfaces of layered photoreceptors.

View full abstract

D. C. transient currents of orgnic layered photoreceptors were measured under various conditions to obtain the information about charge carrier injection at the substrate-CGL (Charge Generation Layer) and CGL-CTL (Charge Transport Layer) interfaces. In the small voltage addition, the D. C. transient currents strongly depended on whether the energy barrier exists or not between CGL and CTL. Similar behavior was observed in transient currents under light irradiation, well corresponding to the residual potential in photo-induced decays of the photoreceptors. It was shown that the variety of corona charge acceptance of photoreceptors due to the purity of CG material, metal-free phthalocyanine in this study, was found to depend on the degree of Schottky-barrier formation between Al substrate and CGL. The concentration of CT compounds in CTL was well reflected on the Fourier transform spectra of transient currents. Space charge polarization process within the photoreceptor occurred more slowly by decreasing the concentration of CT compounds and the value of 15 Å was obtained as the critical intermolecular distance for the charge carrier hopping.

View full abstract