An Avalanche-type X-ray Image Pickup Tube with an amorphous selenium(a-Se) photoconductive layer is investigated. The sensitivity is improved to realise in-situ X-ray photon counting operation by using a thick a-Se layer(25μm) and a BN face plate, and by adopting an electrode for high voltage operation.
Sensing and processing have been performed by a molecular device that immobilizes bacteriorhodopsin as photo-sensitive retinal protein. A thin film of purple membrane fragments containing bacteriorhodopsin was coated on an SnO_2 conductive electrode and was put into contact with an aqueous electrode gel having a counter electrode to construct a sandwich-type photocell. Under visible light irradiaton, the photocell produced a rectified photocurrent that proved to have unique differential responsivity to light intensity, which is characteristic of vertebrate photoreceptors.
Photosynthetic reaction centers (RCs) have a function of light-induced charge separation with high quantum efficiency. We have fabricated stable and close-packed LB films of RCs by optimizing the film preparing conditions. It was observed the light-induced electron transfer even in a monolayer RC-LB film by means of the displacement current measuring technique. A sandwich device of the LB films showed a steady state photocurrent, and the direction of current flow was changed corresponding to an orientation of RCs depending on the wettability of substrates.