The Stand for Research of Positional-Sensitive Photosensor

Abstract

The paper considers position-sensitive photodetectors (PSP), which are designed to detect the source of electromagnetic radiation in the optical range and determine the coordinates of the irradiated area in real time, as well as to track moving optical objects. In particular, data are presented on photodetectors based on photosensitive epitaxial CdSe/mica layers with an unconventional layout and switching of electrical contacts. The output signal of such PSP is the transverse potential difference that appears between its two contacts after exposure of one of the areas of the photodetector. These PSPs can be an alternative or competition to existing photocells due to high accuracy, speed, ease of manufacture and low cost. But there are significant obstacles for their wide application. First, it is an analog type of output signal, which prevents its further processing. And, second, it is difficult to calibrate “manually” a newly made photosensor: it takes a long time associated with the accumulation and processing of large amounts of data. The introduction of computer technology and the creation of an information-measuring system allow us to process the output signals of such photodetectors with high accuracy and speed in real time. To solve this problem we have developed a stand for the study of position-sensitive photodetectors, which is presented in this paper. This stand allows digitizing the signal received from the photodetector, in real time, with high accuracy to determine the coordinates of the irradiated area on the photodetector and explore its characteristics such as the specified value of the dark current of the photodetector, light current at a certain illumination, and output voltage. At this stand, position-sensitive photodetectors based on the CdS/mica system were studied. It is shown that the characteristics and parameters of photoreceivers measured on this stand coincide with theoretical ones, within the error limits. Recommendations on the use of the standare given.