Photoconductive Behavior of Lead Sulfide Films. Volume 2. Appendix IV. Photoconductivity in Chemically-Deposited Lead Sulfide Layers
Photoconductive Behavior of Lead Sulfide Films. Volume 2. Appendix IV. Photoconductivity in Chemically-Deposited Lead Sulfide Layers

Author: Svein Espevik

Publisher:

Published: 1971

Total Pages: 206

ISBN-13:

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Although chemically-deposited PbS layers have been extensively studied over the last twenty-five years, the mechanism of the photoconductivity process in such layers has not been previously understood in any reliable or complete manner. Investigation of the temperature dependence of the electrical conductivity, photoconductivity, Hall coefficient, photo-Hall effect, and thermoelectric power in such layers has been used to answer many of the common questions. Three types of layers have been investigated: (1) without added chemical oxidant in the deposition bath; (2) with a standard proportion of oxidant added; and (3) with four times the standard proportion of oxidant added. Electron microscope studies show that the layers consist of grains and intergranular regions. The author predicts on the basis of this work, that it should be possible in principle to prepare highly photosensitive PbS single crystal detectors.

Photoconductive Behavior of Lead Sulfide Films
Photoconductive Behavior of Lead Sulfide Films

Author: Donald K. Smith

Publisher:

Published: 1971

Total Pages: 180

ISBN-13:

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The structure, chemical composition, and photoelectronic properties of chemically deposited PbS films have been investigated in relationship to variation in the concentration of oxidant used in the deposition. Structure and photoelectronic properties in the PbS film change as the concentration of oxidant is varied. Concomitant variations in the average chemical composition of the films are minor. It was found that the dependence of carrier density and mobility on temperature is divided into low and high temperature regions with distinct activation energies. The principal effect of photoexcitation is to increase the carrier density. Films produced without the use of oxidants are relatively insensitive. The primary electronic properties of PbS films may be described in terms of sensitizing centers located 0.23 eV below the conduction band, and in terms of intergrain barriers which limit the effective mobility. The intergrain barriers play no essential role in the photoconductive process. PbS films deposited from baths containing no oxidant lack the sensitizing centers.