Highly conductive Nb doped SrTiO3 epitaxial thin films grown by laser molecular beam epitaxy

Highly conductive Nb doped SrTiO3 (Nb:STO) thin films with good crystallini ty and smooth surfaces were epitaxially grown on SrTiO3 (STO) (1 0 0) subst rates by laser molecular beam epitaxy. The resistivity, carrier concentrati on and mobility of the Nb:STO thin film are 3.6 x 10(-4) Omega cm, 2.8 x 10 (21) cm(-3) and 12.7 cm(2)/V s, respectively, which are the best values in Nb:STO thin films reported so far. The root-mean-square surface roughness o f the deposited thin him is measured to be 0.240 nm by atomic force microsc opy. The chemical composition and its uniform distribution in the film were confirmed by angle-resolved X-ray photoelectron spectroscopy and Rutherfor d backscattering spectrometry. The difference of electronic structure in th e band gap region between Nb : STO and STO thin films was studied by X-ray photoelectron spectroscopy. (C) 2000 Elsevier Science B.V. All rights reser ved.