Apparatus for measuring fast relaxation processes in extrinsic photoconductors

This paper describes automated apparatus based on a pulsed injection laser, a sampling oscilloscope, and a D3-28 microcomputer for studies at low temperatures of fast relaxation processes in extrinsic photoconductors with the aid of digital signal storage. The authors used semiconductor lasers based on solid solutions of type A /SUP IV/ B /SUP VI/ as sources of long-wave radiation for measuring relaxation characteristics. The time resolution of the described apparatus is <3 nsec and the voltage sensitivity is ca 5 μV with a 50-ohm load for a storage time of ca 15 min. The operation of the apparatus is illustrated by the example of measurements of the relaxation of extrinsic photoconductivity in lightly compensated Si and determination of the concentration of compensating impurities from these measurements