Influence of the growth conditions on the LaAIO3/SrTiO3 interface electronic properties
DPMC, University of Geneva - 24 quai Ernest-Ansermet, 1211 Genève 4, Switzerland
Accepted: 24 June 2010
The effects of oxygen pressure during the growth of LaAlO3 on (001) SrTiO3, and of post-deposition annealing were investigated. While little influence on the structure was observed, the transport properties were found to depend on both growth pressure and annealing. For LaAlO3 layer thicknesses between 5 and 10 unit cells and growth pressures between 10− 4 and 10−2 mbar, the LaAlO3/SrTiO3 interfaces displayed similar metallic behavior with a sharp transition to a superconducting state. At an oxygen pressure of 10− 6 mbar oxygen vacancies were clearly introduced and extended deep into the SrTiO3 crystal. These vacancies could be removed by post-deposition annealing in 0.2 bar of O2 at ∼530 °C. At a growth pressure of 10− 4 mbar, the electronic properties of samples with ultra-thin LaAlO3 layers (2 to 3 unit cells thick) were found to depend markedly on the post-annealing step.
PACS: 73.40.-c – Electronic transport in interface structures / 81.15.-z – Methods of deposition of films and coatings; film growth and epitaxy / 74.70.-b – Superconducting materials other than cuprates
© EPLA, 2010