Studies of photogeneration of charge in polysilanes using thermally stimulated current measurements

Studies of photogeneration of charge in polysilanes resulting from multiple pulse excitation in thermally stimulated current (TSC) measurements are reported. The amount of charge that was photogenerated at 80 K and collected during the heating of the sample up to 300 K, ranged from 1×10−9 to 4×10−8 C/cm2 for electric fields of 10–30 V/μm and illumination energy up to 2.5 mJ/cm2 and was found to be dependent both on the electric fields applied during illumination and thermal ramping and on the illumination energy. The results are compared to an idealized model that qualitatively describes for photogeneration of the charge at 80 K and its collection during the TSC measurement. According to this model, multiple pulse excitation at 80 K leads to a buildup of photogenerated charge density in the surface region of the sample and as the temperature is increased, electron-hole recombination occurs, limiting the amount of charge collected by the external circuit.