title: Homogeneity and variation of donor doping in Verneuil-grown SrTiO3:Nb single crystals.
abstract: The homogeneity of Verneuil-grown SrTiO3:Nb crystals was investigated. Due to the fast crystal growth process, inhomogeneities in the donor dopant distribution and variation in the dislocation density are expected to occur. In fact, for some crystals optical studies show variations in the density of Ti(3+) states on the microscale and a cluster-like surface conductivity was reported in tip-induced resistive switching studies. However, our investigations by TEM, EDX mapping, and 3D atom probe reveal that the Nb donors are distributed in a statistically random manner, indicating that there is clearly no inhomogeneity on the macro-, micro-, and nanoscale in high quality Verneuil-grown crystals. In consequence, the electronic transport in the bulk of donor-doped crystals is homogeneous and it is not significantly channelled by extended defects such as dislocations which justifies using this material, for example, as electronically conducting substrate for epitaxial oxide film growth.
authors: Forschungszentrum Jülich GmbH, Peter Grünberg Institute (PGI-7) and JARA-FIT, 52425 Jülich, Germany.
authors: C
authors: C
authors: Rodenbücher
authors: Forschungszentrum Jülich GmbH, Ernst Ruska-Centre (ER-C) for Microscopy and Spectroscopy with Electrons, 52425 Jülich, Germany.
authors: M
authors: M
authors: Luysberg
authors: RWTH Aachen, Gemeinschaftslabor für Elektronenmikroskopie, 52056 Aachen, Germany.
authors: A
authors: A
authors: Schwedt
authors: RWTH Aachen University, Institute of Electronic Materials (IWE2), 52056 Aachen, Germany.
authors: V
authors: V
authors: Havel
authors: Forschungszentrum Jülich GmbH, Peter Grünberg Institute (PGI-7) and JARA-FIT, 52425 Jülich, Germany.|RWTH Aachen University, Institute of Electronic Materials (IWE2), 52056 Aachen, Germany.
authors: F
authors: F
authors: Gunkel
authors: Forschungszentrum Jülich GmbH, Ernst Ruska-Centre (ER-C) for Microscopy and Spectroscopy with Electrons, 52425 Jülich, Germany.|RWTH Aachen, Gemeinschaftslabor für Elektronenmikroskopie, 52056 Aachen, Germany.
authors: J
authors: J
authors: Mayer
authors: Forschungszentrum Jülich GmbH, Peter Grünberg Institute (PGI-7) and JARA-FIT, 52425 Jülich, Germany.|RWTH Aachen University, Institute of Electronic Materials (IWE2), 52056 Aachen, Germany.
authors: R
authors: R
authors: Waser