CeOx thin films as transparent nanomaterials for efficient gas sensing

This study describes the sensor properties of CeOx thin films fabricated through electron beam evaporation (EBE). For standard EBE deposition, with additional substrate heating at 200°C and Ar⁺ ion assistance. Moreover, an additional Pd film was also deposited as a top catalyst layer (using the EBE technique). GIXRD analysis revealed that the prepared films were nanocrystalline, consisting of CeO₂ crystallites with an average size of approximately 6 nm. The transparency of the CeOx film was >80 % in the visible range. The primary focus of prepared thin-film structures lies in their gas-sensing capabilities, particularly in resistance changes. The gas-sensor response (SR) increased with increasing hydrogen content in the air, as well as with the sensor operating temperature. However, the gas response was achieved at a temperature below 200°C, even at 150°C. These findings underscore the immense potential of CeOx thin-film nanomaterials, which, owing to their high transparency and responsiveness at low temperatures, can be deployed in transparent sensor configurations with low energy consumption.