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

Abstract In this study, it is aimed to produce triple layer TiO 2 /HfO 2 /SiO 2 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 SiO 2 , TiO 2 and HfO 2 film coated silicon substrates were obtained as 93.7%, 82.9% and 86.62%, respectively. The average transmittances for double layer TiO 2 /HfO 2 and Triple layer TiO 2 /HfO 2 /SiO 2 thin films were obtained as 89.41% and 95.44%, respectively. The band gap values of TiO 2 , HfO 2 and SiO 2 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 TiO 2 , HfO 2 and SiO 2 , respectively, while the triple layer TiO 2 /HfO 2 /SiO 2 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.