Photoconductive device and method of operating the same

An imaging device having high sensitivity and low dark current comprising:

• a semiconductor region having an amorphous semiconductor layer into which photons are inserted and converted into electron-hole pairs by photoelectric conversion;
• means for applying a high electric field to the semiconductor region comprising an electrode and an electric power supply;
• and
• means for reducing dark current of the imaging device,
• wherein the amorphous semiconductor layer generates electron-hole pairs under said high electric field such that a number of said electron-hole pairs is larger than the number of incident photons.