The effect of indium oxide (In2O3) dopant on the electrical properties of LiTaO3 thin film-based sensor

Abstract

The effect of the indium oxide (In2O3) dopant on the electrical properties of the lithium tantalate (LiTaO3) thin film-based sensor was investigated in this study. LiTaO3 thin film was made on p-type Si (100) substrates by applying the chemical solution deposition (CSD) method. The LiTaO3 thin film was annealed at the temperature of 850 °C for 15 h. Surface morphology and elemental characterization analysis were obtained by using SEM-EDX (scanning electron microscopy–energy-dispersive X-ray spectroscopy). Then, the dielectric constant value and the photoresistive characteristic of LiTaO3 thin film were measured to determine the effect of the In2O3 dopant on the electrical properties of the thin film. From the SEM-EDX measurement, it is observed that the surface of the thin film is still non-homogeneous; therefore, the electron flow will be obstructed. Based on the elemental atomic composition analysis, it appears that the Indium atoms have appeared in the LiTaO3 thin films doped by In2O3 2%, 4%, and 6%. From the results of thin film dielectric constant calculation, it can be seen that the dielectric constant value between undoped and In2O3-doped LiTaO3 thin film does not change, which is 2.44. The photoresistive value shows that the Indium dopant decreases the resistivity but increases the conductivity of the thin film. Based on the photoresistive characteristic measurement results, it can be concluded that the LiTaO3 thin film can be used as a light sensor, and In2O3dopant can increase the conductivity of the LiTaO3 thin film.