PURPOSE: To hold the emission of thermoelectrons after the irradiation of light is stopped and count it to increase the amount of output charge (sensitiveness) relative to the number of incoming photons by radiating light to a preset half- insulating semiconductor in an electric field of a preset value or more.
CONSTITUTION: A half-insulating semiconductor 1-1 mainly composed of GaAs has both sides provided with a mesh-shaped film electrode 1-2 and a Schottky- type electrode 1-3, respectively, across which voltage is applied to cause not less than 1KV/cm electric field in the semiconductor 1-1. Long wave-length light is radiated from an energy gap in the semiconductor 1-1, so that the Fermi level of the semiconductor moves to a conduction band and the emission of thermoelectrons are increased and still remains in a greatly increased state after the irradiation of light is stopped. In this way, electron current which is taken out of the semiconductor into a vacuum is counted at the timing of light irradiation to know its sensitiveness.
HIROHATA TORU
SUZUKI TOMOKO
IHARA TSUNEO
MIYAZAKI MASAHARU
ARAGAKI MINORU
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