The Role of Cobalt in CuCoSe Alloyed Semiconductor Thin Films: Composition-Driven Band Structure Engineering and Ethanol Sensing

This study highlights that beyond particle size, composition is a key factor in tuning the optical and electronic properties of alloyed semiconductor quantum dots. By precisely adjusting metal ion concentrations, researchers can engineer alloyed nanoparticles and significantly influence their band structure and energy levels. The research focuses on the role of metal ions in an alkaline environment in forming alloyed Metal Selenides, with particular emphasis on cobalt ions in CuCoSe thin films. A new method, DITM, is introduced to determine the bandgap energy more accurately than the traditional Tauc model, as it avoids structural assumptions and provides more reliable optical insights. In CuCoSe alloys, cobalt is not a dopant but an essential component that introduces unique properties. Specifically, a concentration of 0.03 mol of cobalt enhances optical transitions in the infrared region. Ethanol-sensing experiments further confirm the films’ responsiveness, demonstrating their strong potential for optical chemical sensor applications.