Cu2ZnGeS4

Cu2ZnGeS4 is a copper zinc germanium sulfide, a quaternary chalcogenide semiconductor. It belongs to the kesterite-type family and isostructural with the copper zinc tin sulfide analogs (such as Cu2ZnSnS4). The material typically forms a tetragonal crystal lattice where copper, zinc, and germanium occupy distinct cation sublattices coordinated by sulfur. Like related quaternaries, Cu2ZnGeS4 can exhibit cation disorder between the Cu and Zn sites, which influences its electronic properties.

The compound is usually prepared by high-temperature solid-state routes from sulfide precursors or via combinations of Cu, Zn, Ge and S sources. It can also be deposited as thin films by sputtering, chemical vapor deposition, electrodeposition, or solution-based methods, enabling exploration in device contexts. Its chemistry allows tuning through substitutions (for example, replacing S with Se or varying copper content) to adjust properties.

Electronic and optical properties of Cu2ZnGeS4 are typical of direct-bandgap, p-type semiconductors in this family. The bandgap lies in the visible region, making it a candidate for absorber layers in photovoltaic devices. Defect physics, including copper-related acceptors and intrinsic defects, strongly influence carrier concentration and recombination, presenting both opportunities and challenges for device performance.

Research on Cu2ZnGeS4 focuses on its potential for thin-film solar cells and as a tunable, Earth-abundant semiconductor alternative to more common CZTS materials. Ongoing work addresses phase stability, defect engineering, and scalable synthesis to improve efficiency and uniformity. Related compounds include Cu2ZnSnS4 and Cu2ZnGeSe4, which offer comparative insights into structure–property relationships.