Effect of precursor solution molarity on electrical and optical properties of spin-coated titanium dioxide (TiO2) thin films

Abstract

In our study, we investigated the electrical and optical properties of TiO2 thin films deposited on p-type c-Si using the spin coating method at different molarities. We observed that as molarity increased, reflectance values decreased, and the minimum reflectance point shifted toward the middle of the visible range. Additionally, the band gap values obtained from transmittance measurements were determined as 3.05 eV, 3.09 eV, and 3.33 eV for 0.1 M, 0.3 M, and 0.5 M, respectively. When examining the electrical properties of the TiO2 thin films, we observed an increase in resistivity values from 287 to 1284 Ω cm with an increase in molarity, while the carrier density decreased from 5.33 × 1014 to 6.42 × 1013 cm−3. This study emphasizes that high molarity TiO2 thin films improve optical properties, while low molarity is preferable for electrical properties. It also highlights the critical role of molarity as a control parameter in optimizing of TiO2 thin films electrical and optical properties. Graphical abstract: [Figure not available: see fulltext.]