Structure and transport in high pressure oxygen sputter-deposited BaSnO<sub>3−δ</sub>

Ganguly, Koustav; Ambwani, Palak; Xu, Peng; Jeong, Jong Seok; Mkhoyan, K. Andre; Leighton, Chris; Jalan, Bharat

doi:10.1063/1.4919969

Cited by 78 publications

(59 citation statements)

References 29 publications

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“…The increase in n under a reducing atmosphere may be related to the introduction of carrier-generating point defects such as oxygen vacancies or interstitial hydrogen [22][23][24] . Treatment under excessively reducing conditions at high temperature (i.e., 5% H 2 at 950°C) to increase the diffusivity of the point defects led to a significant suppression of the (001) XRD peak and insulating properties of the LBSO epitaxial films; these changes can be attributed to the collapse of the BSO crystal structure due to excessive formation (or incorporation) of oxygen vacancies in BSO (Fig.…”

Section: Resultsmentioning

confidence: 99%

Oxygen vacancy-assisted recovery process for increasing electron mobility in n-type BaSnO3 epitaxial thin films

Yoon

Son

2018

NPG Asia Mater

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The scattering of charge carriers by line defects, i.e., threading dislocations (TDs), severely limits electron mobility in epitaxial semiconductor films grown on dissimilar substrates. The density of TDs needs to be decreased to further enhance electron mobility in lattice-mismatched epitaxial films and heterostructures for application in highperformance electronic devices. Here, we report a strategy for the post-treatment of epitaxial La-doped BaSnO 3 (LBSO) films by delicately controlling the oxygen partial pressure p(O 2 ), which achieved a significant increase in the room temperature (RT) electron mobility (μ e ) to μ e = 122 cm 2 V −1 s −1 at a carrier concentration of 1.1 × 10 20 cm. This mobility enhancement is mostly attributed to an oxygen vacancy-assisted recovery process that reduces the density of TDs by accelerating the movement of dislocations in ionic crystals under a p(O 2 )-controlled treatment despite an increase in the density of charged point defects. Our finding suggests that accurate control of the interactions between point defects and line defects can reduce dominant carrier scattering by charged dislocations in epitaxial oxide semiconductors that have dissimilar substrates. This method provides alternative approaches to achieving perovskite oxide heterostructures that have high RT μ e values.

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Section: Resultsmentioning

confidence: 99%

Oxygen vacancy-assisted recovery process for increasing electron mobility in n-type BaSnO3 epitaxial thin films

Yoon

Son

2018

NPG Asia Mater

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“…SrSnO 3 and BaSnO 3 , with Sn 4+ residing on the B-site, have recently emerged as indium-free transparent conductors [6][7][8] and for oxide electronics due to their high room-temperature electron mobility and wide bandgap. [9][10][11][12][13][14] Mixed valence states may or may not be beneficial, depending on the intended application. For example, Sn 2+ located on the A-sites in BaSnO 3 forms an undesirable anti-site defect, whereas a presence of a small a Author to whom correspondence should be addressed.…”

confidence: 99%

Chemistry, growth kinetics, and epitaxial stabilization of Sn2+ in Sn-doped SrTiO3 using (CH3)6Sn2 tin precursor

et al. 2016

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PbTiO3-based ferroelectrics have impressive electroactive properties, originating from the Pb2+ 6s2 electron lone-pair, which cause large elastic distortion and electric polarization due to cooperative pseudo Jahn-Teller effect. Recently, tin-based perovskite oxide (SnTiO3) containing Sn2+ and a chemistry similar to that of the 6s2 lone-pair has been identified as a thermally stable, environmentally friendly substitute for PbTiO3-based ferroelectrics. However experimental attempts to stabilize Sn2+ on the A-site of perovskite ATiO3 have so far failed. In this work, we report on the growth of atomically smooth, epitaxial, and coherent Sn-alloyed SrTiO3 films on SrTiO3 (001) substrates using a hybrid molecular beam epitaxy approach. With increasing Sn concentration, the out-of-plane lattice parameter first increases in accordance with the Vegard’s law and then decreases for Sn(Sr+Ti+Sn) at. % ratio > 0.1 due to the incorporation of Sn2+ at the A-site. Using a combination of high-resolution X-ray photoelectron spectroscopy and density functional calculations, we show that while majority of Sn is on the B-site, there is a quantitatively unknown fraction of Sn being consistent with the A-site occupancy making SrTiO3 polar. A relaxor-like ferroelectric local distortion with monoclinic symmetry, induced by A-site Sn2+, was observed in Sn-doped SrTiO3 with Sn(Sr+Ti+Sn) at. % ratio = 0.1 using optical second harmonic generation measurements. The role of growth kinetics on the stability of Sn2+ in SrTiO3 is discussed.

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“…3. (a) µ at 300 K as a function of n 3D for BaSnO 3 films grown on SrTiO 3 and PrScO 3 using oxide MBE (this work), and from reports from the literature (Kim et al, 12 Ganguly et al, 9 and Wadekar et al 11 ). The thickness of all films is 32 nm, except for one film on SrTiO 3 (starred), which was 64 nm.…”

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“…BaSnO 3 thin films have been grown using high-energetic deposition techniques, such as sputtering 9 and pulsed laser deposition, 4,10-12 but achieving high mobilities has been challenging. The best reported film mobilities are <80 cm 2 V −1 s −1 at room temperature.…”

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High-mobility BaSnO3 grown by oxide molecular beam epitaxy

et al. 2016

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High-mobility perovskite BaSnO3 films are of significant interest as new wide bandgap semiconductors for power electronics, transparent conductors, and as high mobility channels for epitaxial integration with functional perovskites. Despite promising results for single crystals, high-mobility BaSnO3 films have been challenging to grow. Here, we demonstrate a modified oxide molecular beam epitaxy (MBE) approach, which supplies pre-oxidized SnOx. This technique addresses issues in the MBE of ternary stannates related to volatile SnO formation and enables growth of epitaxial, stoichiometric BaSnO3. We demonstrate room temperature electron mobilities of 150 cm2 V−1 s−1 in films grown on PrScO3. The results open up a wide range of opportunities for future electronic devices.

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Structure and transport in high pressure oxygen sputter-deposited BaSnO_3−δ

Cited by 78 publications

References 29 publications

Oxygen vacancy-assisted recovery process for increasing electron mobility in n-type BaSnO3 epitaxial thin films

Oxygen vacancy-assisted recovery process for increasing electron mobility in n-type BaSnO3 epitaxial thin films

Chemistry, growth kinetics, and epitaxial stabilization of Sn2+ in Sn-doped SrTiO3 using (CH3)6Sn2 tin precursor

High-mobility BaSnO3 grown by oxide molecular beam epitaxy

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Structure and transport in high pressure oxygen sputter-deposited BaSnO3−δ

Cited by 78 publications

References 29 publications

Oxygen vacancy-assisted recovery process for increasing electron mobility in n-type BaSnO3 epitaxial thin films

Oxygen vacancy-assisted recovery process for increasing electron mobility in n-type BaSnO3 epitaxial thin films

Chemistry, growth kinetics, and epitaxial stabilization of Sn2+ in Sn-doped SrTiO3 using (CH3)6Sn2 tin precursor

High-mobility BaSnO3 grown by oxide molecular beam epitaxy

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Structure and transport in high pressure oxygen sputter-deposited BaSnO_3−δ