According to the phase diagram, at room temperature, CdS is almost insoluble in PbS. However, metastable Pb_1-xCd_xS films have been described using both vacuum evaporation and chemical bath deposition (CBD). While there are some reports implying solid solution over a wide range, values of x up to nearly 0.4 (for evaporated films) and 0.2 (for CBD films) have been supported by experimental evidence. For the CBD samples, mixed phases are sometimes reported, and even where this was not the case, it is not clear that only one phase was deposited.
Our experience in repeating previous recipes for Pb_1-xCd_xS is that CdS was also deposited along with the solid solution, but that this CdS is often not seen in XRD (hence it would be easily overlooked if XRD were the main characterization method).
We describe a bath which gives single-phase Pb_1-xCd_xS films with x varying up to 0.15. Because of the small variations in lattice parameters with varying x, we use not only accurate XRD, but also atomic absorption chemical analysis for characterization.
Few studies have been made on the optical absorption (transmission) spectra of these solid solution films and none on CBD films. We correlate these optical spectra with the film composition and find, as did earlier studies using evaporated films, that the optical bandgap is a strong function of the Cd concentration, with a bandgap of ca. 0.9 eV obtained for the highest Cd contents (compared to 0.4 eV for pure PbS). This increase in bandgap is much stronger than expected based on a simple linear relationship between PbS and (rocksalt) CdS with a bandgap of ca. 1.7 eV.

• Legal notice:
  

  Copyright (c) Pielaszek Research, all rights reserved.
  The above materials, including auxiliary resources, are subject to Publisher's copyright and the Author(s) intellectual rights. Without limiting Author(s) rights under respective Copyright Transfer Agreement, no part of the above documents may be reproduced without the express written permission of Pielaszek Research, the Publisher. Express permission from the Author(s) is required to use the above materials for academic purposes, such as lectures or scientific presentations.
  In every case, proper references including Author(s) name(s) and URL of this webpage: https://science24.com/paper/11577 must be provided.