An Epitaxial Transparent Conducting Perovskite Oxide: Double-Doped SrTiO3

Epitaxial thin films of strontium titanate doped with different concentrations of lanthanum and oxygen vacancies were grown on LSAT substrates by pulsed laser deposition technique. Films grown with 5-15% La doping and a critical growth pressure of I 10 mTorr showed high transparency (> 70-95%) in the UV-visible range with a sheet resistance of 300-1000 Omega/square. With the aid of UV-visible spectroscopy and photoluminescence, we establish the presence of oxygen vacancies and the possible band structure, which is crucial for the transparent conducting nature of these films. This demonstration will enable development of various epitaxial oxide heterostructures for both realizing opto-electronic devices and understanding their intrinsic optical properties.