Investigation on structural, optical and electrical properties of Nd doped titania films and application of optical model

The effect of dopant concentration and temperature on the structural, optical and electrical properties of TiO2 (Titania) thin films deposited through sol-gel spin coating was investigated. The X-Ray Diffractometer was used for phase analysis, UV-Vis spectrometer and Ellipsometer techniques were used for the optical measurements and Hall effect was used for the electrical characterization. Annealing temperature and dopant concentration were chosen as the parameters in the present study. The optical band gap marginally increased from 3.40 eV to 3.43 eV with increase in dopant concentration for the films annealed at 350 degrees C. The increasing trend was also observed for the films annealed at 450 degrees C with the optical band gap in the range 3.34 eV-3.39 eV. Using ellipsometric measurement, thickness and optical constants were obtained and we compared the refractive index values with those obtained from PARAV software. For Nd doped films, a single oscillator model was tested by using the refractive index values from ellipsometric measurement. The carrier density and plasma frequency were calculated using the Wemple Di Domenico (W-D) model. The electrical properties indicate decreased resistivity from 103 omega cm to 101 omega cm and increased carrier density from 10(15) cm-3 to 10(17) cm(-3) with increase in annealing temperature. Similarly, with increase in dopant concentration at a given annealing temperature, we have observed a decreased resistivity compared to the prestine samples. However, the carrier density increased marginally with increase in dopant concentration.

Automated summary

The study explored the impact of dopant concentration and temperature on the structural, optical, and electrical properties of TiO2 thin films. It was found that the optical band gap varied with dopant concentration and annealing temperature, while electrical properties exhibited decreased resistivity and increased carrier density with increasing temperature or dopant concentration.