Tuning Optoelectronic Properties of Ta Doped SrTiO3 Thin Films

Abstract

in this thesis. The initial part of the study focused on the optimization of Pulsed Laser Deposition (PLD) grown Ta-doped SrTiO3 epitaxial films. The structural and optoelectronic properties of the films ere systematically varied by changing the growth temperature and oxygen partial pressure during PLD. The crystalline phase of the epitaxial films was found to be improved by incorporating Ta in the lattice. This was however influenced by the growth temperature, as demonstrated by Rutherford Back Scattering channelling and High-Resolution X-ray diffraction. A systematic study was conducted further by varying Ta concentration in STO to observe the effect on the lattice parameter both experimentally and theoretically by Density Functional Theorem (DFT). After stabilizing its crystal structure, optical studies were performed by Ultraviolet-Visible spectroscopy and Ellipsometry, and the results were supported by band structure calculations with DFT. Finally, the electrical properties of these films as a function of Ta concentration were investigated, and it was established that these films are promising for visible range transparent conductor as well as resistive switching devices.