Hydrogen peroxide (H₂O₂), a byproduct of cellular metabolism, is a critical biomarker whose overexpression has been linked to diseases such as cancer and Parkinson’s. Its precise and sensitive detection is essential for advancing diagnostics and disease monitoring. Tin dioxide (SnO₂) has been extensively studied for H₂O₂ detection, while other tin oxides, such as tin monoxide (SnO), remain less investigated. Given that higher surface-to-bulk ratios enhance the sensitivity in electrochemical sensors, this study aims to establish a correlation between the composition, structure, morphology, and electrochemical response of Sn–O thin films in H₂O₂ solutions to advance non-enzymatic H₂O₂ biosensors.

Sn–O thin films were synthesized using reactive DC magnetron sputtering at room temperature, with and without the Glancing Angle Deposition (GLAD) technique, by varying the oxygen partial pressure. The films were characterized using Scanning Electron Microscopy, Energy Dispersive X-ray Analysis, Wide-Angle X-ray Scattering, and Cyclic Voltammetry.

The results revealed that the films exhibited a range of compositions from SnO_0.41 (71% Sn, 29% O) to SnO_0.67 (60% Sn, 40% O) and consisted of a mixture of phases, including metallic tin and various metastable tin oxides (SnO, Sn₃O₄, and SnO₂). Morphological analysis showed that increased oxygen content led to larger columnar structures and slightly smoother surfaces due to enhanced atomic mobility. GLAD further modified the morphology by increasing the column size and introducing open structures. However, electrochemical analysis demonstrated the inert behavior of all synthesized Sn- O films toward H₂O₂ detection, with no significant catalytic activity observed under the tested conditions. Interestingly, GLAD-deposited SnO_0.45 and SnO_0.67 films exhibited capacitive behavior indicative of electric double-layer capacitors, highlighting their potential for energy storage applications.

This thesis provides valuable insights into the fabrication and properties of Sn–O thin films and sets a foundation for further investigation toward the development of non- enzymatic H₂O₂ biosensors.