Optimization of carrier mobility in Pr-doped SrTiO3 thin films through controlled Sr-segregation for optoelectronic applications

Functional oxides employed in electronic components hold significant promise for future electronic devices. Strontium titanate based thin films have several emergent features due to unsaturated bonds, dimension restriction, production of oxygen vacancies and point defects that make them attractive for optoelectronic applications. Here we prepared Pr-doped strontium titanate thin films via RF magnetron sputtering in a pure Argon environment at various gas pressures followed by heat treatment. The structural parameters, analyzed via XRD and Raman spectroscopy, were correlated with the electrical transport properties. Intriguing morphological features such as Stranski–Krastanov (SK) growth and cation segregation observed by FESEM and AFM analysis were further examined to elucidate the conduction mechanism in the films. The optical studies unveiled significant transparency in the visible spectrum. Photoluminescence emission studies at specific wavelengths shed light on the involvement of oxygen vacancies. By carefully controlling annealing conditions and optimizing sputtering parameters, thin films devoid of Sr segregation with highest reported carrier mobility of 33.9 cm²/V s were prepared. The high mobility leading to enhanced conductivity render the films suitable for a wide range of optoelectronic applications.