Plasma-driven defect modulation in ZnO thin films for superior UV sensing

초록

Plasma treatment offers an effective approach to tailoring the electrical, optical, and surface properties of ZnO thin films for high-performance ultraviolet (UV) photodetector applications. In this study, ZnO thin films were treated with different plasma gases−Ar, O2, CF4, and Cl2−to investigate the influence of plasma-induced modifications on defect states, carrier dynamics, and surface morphology of ZnO thin films. Plasma treatment influenced the oxygen vacancies, work function, and band structure, leading to changes in charge transport and optical absorption properties. Ar plasma introduced oxygen vacancies, enhancing free carrier concentration, whereas O2 plasma reduced defect states, shifting the Fermi level. CF4 and Cl2 plasmas modified the ZnO lattice by substituting oxygen with halogen elements, altering donor levels. Additionally, plasma treatment influenced the surface roughness of the films, demonstrating a strong correlation between plasma chemistry and material properties. These results highlight plasma processing as an effective strategy for optimizing ZnO-based optoelectronic devices, enabling precise defect engineering and enhanced photodetector performance.

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