Electrical characterization of semiconducting La doped SrTiO3 thin films prepared by pulsed laser deposition

We present the growth of La doped SrTiO3 thin films on MgAl2O4 (100) substrates using the Pulsed Laser Deposition (PLD) technique. The crystal quality of the films was analyzed by X-Ray Diffraction (XRD) and Rutherford Backscattering Spectroscopy (RBS). A substitution of La on the Sr sites can be deduced for several La concentrations from the RBS measurements in combination with Hall measurements. Temperature dependent conductivity measurements using the van der Pauw technique reveal the semiconducting behavior of the films. The conductivity of the samples at room temperature can vary over several orders of magnitude depending on the La concentration in the films and the oxygen partial pressure during PLD. The Hall mobility of the films was found to be temperature dependent and is about 3 cm2/Vs at room temperature, in contrast to bulk single crystals, where the mobility is known to be 6 cm2/Vs. A scattering mechanism is proposed to explain the observed mobility behavior.