Photoinduced Discharge Characteristics

The xerographic spectral response for both a-Sbo.03Seo.97 and pure Se are shown in Fig. 7.4. 

For the films under examination, the residual voltage (a measurable surface potential at the end of the illumination) increases with the Sb content (Fig. 7.5). 

The residual potential is due to trapped electrons in the bulk of the specimen. The simplest theoretical model, which is based on range limitation and weak trapping (Vj c Vo) relates to /ir (the drift mobility and lifetime r product) via the Warter equation [19]  

As described earher [20], the saturation residual potential provides an experimental measure of the integrated number of deep traps (trap-release rates are much slower than those from shallow traps which control drift mobihty). Vk is then simply given by 

Both the first residual and the cycled-up saturated residual potential are sensitive to alloying. For example, when pure amorphous Se films are alloyed with antimony, the buildup of the residual potential occurs more rapidly toward a much higher saturated residual potential. We obtain, for instance, Aij 2 X lO cm and Ni lO cm for a-Se and Sbo.osSeo.gT, respectively. 

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