Advanced Physical Research

This work presents a comprehensive investigation of the microstructural, compositional, structural, and electrophysical properties of diode structures based on Cd-rich Zn–Cd–S thin films prepared by gas transport deposition using hydrogen as the carrier gas. The films were deposited from a mixed ZnS–CdS powder source, leading to the formation of Cd-rich ternary Zn–Cd–S semiconductor layers. The surface morphology was investigated by scanning electron microscopy (SEM), revealing a dense polycrystalline microstructure composed of irregularly shaped grains and well-developed crystalline domains. Energy-dispersive X-ray spectroscopy (EDS) qualitatively confirmed the presence of Zn, Cd, and S as the principal constituent elements of the deposited films, while minor amounts of O, C, and Na were attributed to surface oxidation, environmental contamination, or residual impurities. Elemental mapping demonstrated a generally uniform spatial distribution of the constituent elements with only minor local compositional variations characteristic of nonequilibrium vapor-phase growth. X-ray diffraction (XRD) analysis confirmed the formation of polycrystalline Cd-rich Zn–Cd–S semiconductor films exhibiting the coexistence of cubic and hexagonal structural modifications. Phase identification was performed by comparison with standard crystallographic reference data, confirming successful formation of the ternary semiconductor alloy. The observed diffraction features indicate that the crystal structure is governed by the combined effects of alloy formation and nonequilibrium growth during gas transport deposition. The electrophysical properties of the fabricated diode structures were investigated using current–voltage (I–V) measurements. The devices exhibited pronounced rectifying behavior, confirming the formation of a barrier-type semiconductor junction. The electrical response is interpreted in terms of thermionic emission, recombination through defect-related states, grain-boundary potential barriers, interface states, and defect-assisted carrier transport. Overall, the results demonstrate that Cd-rich Zn–Cd–S thin films prepared by gas transport deposition are promising semiconductor materials for diode and optoelectronic applications. The combined structural, compositional, and electrical characterization provides a comprehensive understanding of the relationships between film microstructure, crystal structure, and electrical performance, providing a basis for further optimization of gas-transport-deposited Zn–Cd–S thin films.