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Chalcogenides

Chalcogenide materials are predominantly formed by one or more Group VIA elements in the periodic table (except oxides, which form a material class of their own). Chalcogenide bulk glasses have been extensively studied in the last century. Thin films of chalcogenides have not been explored in depth (until the 2000s), primarily due to difficulties in vacuum based thin film deposition and toxicity concerns. Although the solar industry explored different flavors of chalcogenides, including CdTe, ZnTe, ZnSe, CIGS, etc., the introduction of these materials in other industries such as semiconductor, photonics, and thin film optical coatings has been limited.

Chalcogenide materials and thin films are widely used, due to their versatile electrical, optical, and chemical properties. These uses range from application in non-volatile memory (such as phase change memory, selectors, and optical memory); optics and photonics (for non-linear optics, such as photonic crystals and waveguides); chemical, photo, and image sensors; energy conversion (thermoelectric energy generators and solar cells); as well as displays and LEDs (such as phosphors, quantum dots, or channel material for TFTs).

Due to this versatility in material properties, several industries (including semiconductors), have renewed interest in exploring applications based on chalcogenides thin films and bulk. However, such development requires application dependent materials exploration to determine the composition sweet-spot and material property optimization of chalcogenides.

Over the years, IMI has explored and developed thin film materials and stacks by physical vapor deposition (PVD) and atomic layer deposition (ALD) optimizing material properties by doping and alloying bandgap engineering, defect, and interface control, to enable active device and passive applications in applications such as semiconductor, display, and glass coatings.