Production of Nb2O5 thin films in different thicknesses by sol-gel coating method and their H2 sensor applications

In this thesis, Nb2O5 thin films were deposited on n-type Si and glass substrates by changing the number of layers (film thickness) by sol-gel rotating coating technique. The produced Nb2O5 thin films; Structural, morphological and optical properties were determined using XRD, SIMS, AFM and UV-Vis spectrometry, respectively. It was observed that Nb2O5 thin films have amorphous structure and their transmittance spectra change in the visible region range due to the interference of light on the film/air and film/substrate interfaces. The optical band gap of the films narrowed from 3.76 eV to 3.62 eV as the number of layers increased. The thicknesses for SG43, SG44 and SG45 thin films were determined as 68 nm, 104 nm and 176 nm, respectively. Silver (Ag) circular interdigital electrodes with a diameter of 2 mm were developed with the Aerosol Jet 5X Printing System for the SG43, SG44 and SG45 samples produced, and the resulting H2 gas sensors were named SG43-S, SG44-S and SG45-S.The sensitivity of the developed sensors to Hydrogen (H2) gas was measured at roomtemperature and under 30 sccm, 60 sccm and 90 sccm. Sensor parameters such as sensitivityto H2 gas, response and recovery time of Nb2O5 based H2 gas sensors were evaluated. As aresult of experimental research; It has been shown that the 1, 2 and 3-layer Nb2O5-basedsensors produced are successful sensors in H2 detection at room temperature.