Vacancies and small polarons in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi mathvariant="normal">SrTiO</mml:mi><mml:mn>3</mml:mn></mml:msub></mml:math>

Janotti, Anderson; Varley, Joel B.; Choi, Minseok; Walle, Chris G. Van de

doi:10.1103/physrevb.90.085202

Cited by 210 publications

(192 citation statements)

References 34 publications

Supporting

Mentioning

170

Contrasting

Order By: Relevance

“…Therefore, it can be inferred that our mild reducing conditions produced oxygen vacancies in only the LBSO epitaxial layers and are not sufficient to produce oxygen deficiency in the STO substrates. This selective formation of oxygen vacancies in LBSO/STO can be explained by the fact that the formation energy of oxygen vacancies in STO (~3.1 eV) 29 is considerably higher than that in BSO (~1.7 eV) 24 . To gain further insight into electron transport in the LBSO epitaxial films, we measured the temperature dependence of n and μ e for 1% La-doped LBSO films treated under different conditions (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

View full text Add to dashboard Cite

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.

show abstract

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

View full text Add to dashboard Cite

show abstract

“…We note that luminescent oxygen vacancies have also been observed and calculated in other metal oxides, such as SrTiO 3 , in which the level is present at 0.4 eV below the CB edge. [55][56][57] As described above, solid-state NMR indicates a significant increase in the concentration of substitutional H O following H 2 annealing. Therefore, we also apply DFT to determine the effect of incorporating a hydrogen atom onto an oxygen vacancy center.…”

Section: Oxygen Vacancies In Bivomentioning

confidence: 98%

Role of Hydrogen in Defining the n-Type Character of BiVO₄ Photoanodes

Cooper¹,

Scott²,

et al. 2016

View full text Add to dashboard Cite

The roles of hydrogen impurity and oxygen vacancy defects on defining the conductivity, and hence photoelectrochemical (PEC) performance characteristics, of monoclinic scheelite bismuth vanadate (BiVO4) are investigated using a combination of experiment and theory. We find that elemental hydrogen is present as an impurity in as-synthesized BiVO4 and that increasing its concentration by annealing in H2 at temperatures up to 290 °C leads to near-complete elimination of majority carrier transport limitations, a beneficial shift in the photoanodic current onset potential, and improved fill factor. Magnetic resonance measurements reveal that hydrogen can be incorporated in at least two different chemical environments, which are assigned to interstitial and substitutional sites. Incorporation of hydrogen leads to a shift of the Fermi level toward the conduction band edge, indicating that n-type character is correlated with increased hydrogen content. This finding is in agreement with theory and reveals that hydrogen acts as a donor in BiVO4. Sub-bandgap photoluminescence is observed from as-synthesized material and is consistent with deep electronic states associated with oxygen vacancies. Hydrogen treatment leads to reduced emission from these states. These findings support the conclusion that hydrogen, rather than oxygen vacancies, is dominant in determining the n-type conductivity of BiVO4. These findings have important implications for controlling the electronic properties and functional characteristics of this promising photoanode material.

show abstract

“…Hybrid functionals, on the other hand, combine exact Hartree-Fock exchange with GGA, and have been shown to improve the description of strongly localized carriers. [3][4][5][6] They have also proven accurate in the description of defects in a wide variety of semiconductor systems, correcting the band-gap problem of LDA and GGA. 7 These advantages make DFT with hybrid functionals very well suited for the study of barium cerate.…”

Section: Introductionmentioning

confidence: 99%

Small polarons and point defects in barium cerate

2015

Self Cite

View full text Add to dashboard Cite

Barium cerate (BaCeO3) is a well-known ionic conductor of both hydrogen and oxygen. In applications, it is frequently doped (for instance with Y) to increase stability and promote diffusion. However, the effects of doping and native defects are not fully understood. Computational studies have been stymied by the nature of the conduction band, which is made up of cerium 4f states. These states present a challenge to ab initio techniques based on density functional theory within the standard approximations for exchange and correlation. Using a hybrid functional, we investigate the effects of hydrogen impurities and native defects on the electrical and optical properties of BaCeO3. We discuss the tendency of excess electrons or holes to localize in the form of small polarons. We also explore the interactions of polarons with hydrogen impurities and oxygen vacancies, and their impact on luminescence properties.

show abstract

Vacancies and small polarons inSrTiO3

Cited by 210 publications

References 34 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

Role of Hydrogen in Defining the n-Type Character of BiVO₄ Photoanodes

Small polarons and point defects in barium cerate

Contact Info

Product

Resources

About

Vacancies and small polarons inSrTiO3

Cited by 210 publications

References 34 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

Role of Hydrogen in Defining the n-Type Character of BiVO4 Photoanodes

Small polarons and point defects in barium cerate

Contact Info

Product

Resources

About

Role of Hydrogen in Defining the n-Type Character of BiVO₄ Photoanodes