Triple layer TiO₂/HfO₂/SiO₂ thin film design for reduction of optical losses

In this study, it is aimed to produce triple layer TiO2/HfO2/SiO2 thin films by spin coating method and to minimize optical losses. The characterizations in the study were primarily carried out using XRD, SEM and transmittance and reflectance analyses. The average optical transmittance (400-700 nm) of single layer SiO2, TiO2 and HfO2 film coated silicon substrates were obtained as 93.7%, 82.9% and 86.62%, respectively. The average transmittances for double layer TiO2/HfO2 and Triple layer TiO2/HfO2/SiO2 thin films were obtained as 89.41% and 95.44%, respectively. The band gap values of TiO2, HfO2 and SiO2 thin films produced as single layer were calculated as 3.89 eV, 5.62 eV and 5.52 eV, respectively. The average reflectance (380-1100 nm) for single layer films was measured as 13.26%, 10.52% and 17.76% for TiO2, HfO2 and SiO2, respectively, while the triple layer TiO2/HfO2/SiO2 configuration showed a significant decrease in the average reflectance, reaching 7.74% (380-1100 nm), while a minimum reflectance value of 0.3% was obtained at 605 nm.