Ultrarotdurchlässigkeit und Struktur abschreckend kondensierter Schichten von PbS, PbSe und PbTe

Abstract

Thin films of the lead chalcogenides PbS, PbSe and PbTe are condensed from the vapor onto substrates at low temperature. After condensation and during heating the infrared transmission between 0.8 and 18 μ is measured. Debye-Scherrer-diagrams also are sketched for investigating the structure of the layers. After condensation at 20° K the thin films are amorphous. Depending on the conditions of evaporation the layers crystallize at 83° K or at 115° K (PbS at 135° K) into the normal structure of NaCl-type. During crystallisation the infrared absorption edge moves to longer wavelengths. The high amount of covalent bond seems to be essential for the appearence of the amorphous phase when the substances are condensed on a substrate at low temperature.