Structural, Optical, and Electrical Characteristics of Titanium Dioxide Thin Films Prepared by Pulsed Laser Deposition

Abstract

In this research, the Pulsed Laser Deposition (PLD) technique was used, and the operating frequency of the laser was tuned to a double frequency. This was done in order to construct nano-thin films of titanium oxide (TiO₂). An Nd-YAG laser with a wavelength of 1064 nm, pulse frequency of 6 Hz, and laser energy of 700, 800, and 900 mJ were used on glass and Si (p-type) substrates of different thicknesses. Then, the TiO₂ films were annealed for 2 hours at a temperature of 400 °C. UV-Vis spectra revealed that TiO₂ has strong UV absorption, as well as a large energy gap (2.9, 3.06, and 3.3) eV for energy levels (700, 800, and 900) mJ in contrast. In addition, FESEM analysis showed a granular morphology that showed a tendency for fragmentation into smaller particles with the growth of the thickness of the sample. The thickness of the thin films was determined using the FESEM cross-section, and the results showed that the thicknesses were 278.01, 1630.53, and 2579.66 nm for TiO₂ at laser energy of 700, 800, and 900 mJ, respectively. As the laser energy increased, the results showed an increase in the thickness of the thin film. In addition, the absorbance increased while the transmittance decreased with increasing thin film thickness. In terms of the electrical properties of the cell, we found that the efficiency of the annealed cell was significantly increased compared to that of the unannealed cell.