2 a d positive 800 1000 1 20 0 100 lownegative 800 1000 1 20 10 200 lowtwo layered plate indium doped tellurium selenium arsenic interfacial layer example 2 a c positive 800 1000 1 20 0 100 lownegative 600 800 5 100 50 250 high______________________________________ plates of examples 1 and 2 were tested for spectral sensitivity the results of which are illustrated by the curves in fig3 for this purpose the photoreceptor was corona charged to 800 volts of initial potential either in positive or negative charging mode to obtain the respective spectral sensitivity curve the photoreceptor was then irradiated with monochromatic radiation as obtained from a 350 watt xenon lamp source using either band pass filters or a monochromator from 400 nanometer through 800 nanometer the photoreceptor was allowed to photo discharge to half its original potential for a given energy of radiation the difference in potential for a given amount of light energy was plotted against the respective wavelength ______________________________________spectral sensitivity curves indium doped amorphousselenium arsenic photoreceptor example 1 ______________________________________curve 18 negative charging single layercurve 20 positive charging single layer______________________________________ ordinate relative spectral sensitivity volt microjoule centimeter sup 2 abscissa radiation wavelength nanometer similar relationship was obtained with two layered indium doped amorphous selenium arsenic photosensitive layers as represented by examples 2 a d or 2 b d also similar experiments were done with tellurium sensitized indium doped amorphous selenium arsenic or selenium photosensitive layers as represented by examples 2 a c or 2 b c very similar relationship is obtained spectral broadening in both charging modes occur which primarily depends on the proportion.