Epitaxial growth and transport properties of Nb-doped SrTiO3 thin films

Nb-doped SrTiO3 epitaxial thin films have been prepared on (001) SrTiO3 substrates using pulsed laser deposition. A high substrate temperature (>1000°C) was found to be necessary to achieve 2-dimensional growth. Atomic force microscopy reveals atomically flat surfaces with 3.9 a steps. The films show a metallic behavior, residual resistivity ratios between 10 and 100, and low residual resistivity of the order of 10-4Ωcm. At 0.3 K, a sharp superconducting transition, reaching zero resistance, is observed.