CHECKING OF PARAMETERS OF SEMICONDUCTOR-MATERIALS AND PHOTO DETECTORSBY MODULATORS OF THEIR RADIATION ON HOT CHARGE-CARRIERS

The article deals with a rapidly acting (10(-10) sec) modulator of inf rared radiation including the radiation of a CO2 laser whose operation is based on new physical phenomena and whose operating principle has no analogs in other countries. The modulator is intended for determini ng the characteristics of low-inertia semiconductor radiation detector s in the range of the atmospheric window 9-12 mum, and also for determ ining the photoelectric parameters of semiconductor materials and epit axial structures that are used for radiation detectors. These paramete rs can serve as measure of the defectiveness of materials and structur es. The article describes briefly the operating principle of the modul ator, the design of the modulating element (a p-type germanium crystal ) with a heat-removal unit and a cryostat with high-frequency supply o f control power. The advantages of the suggested modulator are the pos sibility of effecting pulsed as well as continuous modulation, a combi nation of low inertia and broad passband (10(3)-10(10) Hz) while the f requency characteristic is uniform. The depth of modulation in pulsed regime is up to 35%, in continuous regime up to 7%, with control power up to 6 W. The article presents the block diagram of the installation for investigating the parameters of materials, structures, instrument s with the aid of the suggested modulator. As an example, it presents the results of the investigation of the time of the photoconductive re sponse of rapid detectors of IR radiation based on the solid solutions CdxHg1-xTe.