Epitaxial DyScO₃films as passivation layers suppress the diffusion of oxygen vacancies in SrTiO₃

Abstract

The annealing behaviour of oxygen vacancies introduced by epitaxial growth of DyScO3 or SrTiO3 films on SrTiO3 substrates was studied by positron annihilation. Many oxygen vacancies (VO) were introduced near the interface in SrTiO3 substrates when 10 nm DyScO3 or 20 nm SrTiO3 films were grown by pulsed laser deposition at 10−2 Torr or 10−6 Torr oxygen pressure, respectively. Post-annealing in oxygen ambient could partly compensate those vacancies in the SrTiO3/SrTiO3 samples while no vacancy compensation was observed in the SrTiO3/DyScO3 or SrTiO3/DyScO3/SrTiO3 heterostructures. This suggests that epitaxial DyScO3 films can be used as passivation layers to suppress the diffusion of oxygen vacancies.

Tunable electronic transport properties of DyScO3/SrTiO3 polar heterointerface

“…18 However, when PO 2 increases to above 10 −4 mbar, the corresponding peak reduces to very weak intensity, barely distinguished from the curve of pure STO substrate, 18 implying very low density of oxygen vacancies. These results also demonstrate that DSO layer prevents the oxygen compensation in STO substrate, as also reported by Yuan et al, 19 especially for the samples grown at high vacuum ͑10 −6 and 10 −5 mbar͒. For the samples grown at PO 2 =10 −4 mbar, the sheet carrier density drops off to approximately 10 14 cm −2 ͑not shown͒ which approaches the calculated value from the "polar discontinuity" model ͑about 3.28ϫ 10 14 cm −2 ͒.…”

Influence of the growth conditions on the LaAIO 3 /SrTiO 3 interface electronic properties

“…thick LAO layer and the PLD process. A possible mechanism responsible for the creation of oxygen vacancies in the STO substrate has been recently discussed in studies of the growth kinetics of oxide thin films [28,29]. In these works, an oxygen transfer process has been shown to occur from the film to the substrate during the PLD growth.…”

Probing orbital ordering in LaVO3 epitaxial films by Raman scattering

“…8,15 The temperature dependence of the resistance of LaVO 3 on DSO (110) 8 is in stark contrast to the behavior of the resistance of LaVO 3 films on STO(100) substrates, for which metallic-like behavior was measured by several groups. 4,7,8 DSO, which is a better insulator and is less prone to become oxygen deficient or get reduced, 11,31 preserves an insulating surface during and after the LaVO 3 deposition. Temperature-dependent dc resistivity measurements of LaVO 3 single crystals show the onset of the G-type OO by the kinks in the curve, occurring at 141 K. 1 However, no similar kinks have been observed or reported for resistivity data on thin film LaVO 3 samples on various substrates.…”