Perspectives for the creation and application of heterophase material CdS-FeS obtained by the Langmuir–Blodgett method

Background and Objectives: Cadmium sulfide (CdS) is one of the most promising materials for photovoltaic devices, but it is increasingly used as part of complex heterostructures and heterophase materials that provide expanded functionality and perspective for use. This article presents the results of studies on the production of semi-magnetic semiconductor material CdS-FeS, conventionally designated CdS:Fe, using the Langmuir–Blodgett technology. The morphology of the surface layers and the photoelectric characteristics of the obtained material are considered in detail in comparison with the original sample. Methods: A nanosized coating of iron arachinate (ArchFe) was prepared on the surface of CdS using the Langmuir–Blodgett method. The parameters of ArchFe monolayers were controlled using compression isotherms. The CdS/ArchFe structure was annealed in air. Energy-dispersive analysis and mass spectrometric studies were carried out to control the current processes before and after annealing. The main methods for studying hybrid structures of CdS/ArchFe and heterophase material CdS:Fe were atomic force microscopy and analysis of photoelectric characteristics using steady-state and kinetic approaches. Results: The resulting material is a matrix of Cd$_x$Fe$_{1-x}$S solid solution with nanoinclusions of the FeS phase. Analysis of atomic force microscopy images has confirmed the high reproducibility of the proposed method. We have shown the occurrence of the effect of "negative photofatigue" and an increase in integral photosensitivity by 70 times for a heterophase sample compared to "pure" CdS. Conclusion: It has been shown that the resulting material has unique properties, such as increased photosensitivity and negative photofatigue, which is very perspective for creating devices that can operate in conditions high illumination and whose characteristics can be controlled by illumination.