High-sensitivity HARP photoconductive film
Details
We have been developing high-sensitivity HARP photoconductive films made of mainly amorphous selenium, which make use of avalanche multiplication phenomenon. Aiming to improve the sensitivity and the picture quality, we developed the thicker HARP film with an avalanche multiplication factor of about 200, and the Te-doped HARP film with a photoelectric-conversion efficiency for red light of double the previous one. In the developmental process, we found heat treatment to suppress occurring of an image defect when the films were shooting an intense spot light. Moreover, we made an experimental HARP film using a CdSe photoelectric-conversion layer. The film has photoelectric-conversion efficiencies of over 80% almost all over the visible-light-wavelength region, and an avalanche multiplication factor of about 4.
