Point defect distribution in high-mobility conductive<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mtext>SrTiO</mml:mtext></mml:mrow><mml:mn>3</mml:mn></mml:msub></mml:mrow></mml:math>crystals

Gentils, A.; Copie, O.; Herranz, G.; Fortuna, F.; Bibès, Manuel; Bouzéhouane, K.; Jacquet, Éric; Carrétéro, C.; Basletić, Mario; Tafra, Emil; Hamzić, Amir; Barthélémy, A.

doi:10.1103/physrevb.81.144109

Cited by 23 publications

(28 citation statements)

References 34 publications

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“…To identify the defects responsible for PPC, positron lifetime measurements were carried out on as-received and annealed samples before and after illumination. Positron lifetime spectroscopy has been used to characterize vacancy defects in SrTiO 3 [19][20][21]34] as well as in other oxide materials such as ZnO [35,36]. In the present study, measurements were performed using a conventional fast-fast time coincidence spectrometer [37] with two BaF 2 -ray detectors mounted on photomultiplier tubes in collinear geometry, with an estimated time resolution of $200 ps.…”

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confidence: 99%

Persistent Photoconductivity in Strontium Titanate

2013

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Persistent photoconductivity was observed in strontium titanate (SrTiO(3)) single crystals. When exposed to sub-bandgap light (2.9 eV or higher) at room temperature, the free-electron concentration increases by over 2 orders of magnitude. After the light is turned off, the enhanced conductivity persists for several days, with negligible decay. From positron lifetime measurements, the persistent photoconductivity is attributed to the excitation of an electron from a titanium vacancy defect into the conduction band, with a very low recapture rate.

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confidence: 99%

Persistent Photoconductivity in Strontium Titanate

2013

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“…Effect of n-type doping for T bomb = 135 s is weakened compared with that for T bomb = 45 s (not shown). This can be the result of the increase of titanium vacancies and the clustering of oxygen vacancies [13], [14]. Carriers are potentially scattered more by increasing defects as the result of longer bombardment, which slow the mobility.…”

Section: Resultsmentioning

confidence: 98%

Performance Improvement of ${\rm HfO}_{2}/{\rm SrTiO}_{3}$ Hetero-Oxide Transistors Using Argon Bombardment

Zhu

Luo

et al. 2013

IEEE Electron Device Lett.

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An effective interface engineering method is developed to improve performance of SrTiO 3 -based hetero-oxide transistors. HfO 2 /SrTiO 3 hetero-oxide transistors made on argon ions bombarded SrTiO 3 surfaces show eight times increase in drive currents and more than five times increase in mobility when compared with the un-bombarded HfO 2 /SrTiO 3 transistors. The improvement is attributed to the Fermi-level shift as the results of the bombardment. These HfO 2 /SrTiO 3 -based nMOSFETs show field-effect electron mobility up to 4.2 cm 2 /Vs, which is among the best results ever reported.Index Terms-Argon bombardment, channel doping, HfO 2 /SrTiO 3 , MOSFET, oxide.

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“…Many computational studies reported in the literature are focused on defects that affect electrical properties (Mackie et al 2009), especially vacancy defects (Gentils et al 2010;Keeble et al 2010). In the work reported here, changes in properties such as conductivity are not of immediate interest.…”

Section: Materials Modelmentioning

confidence: 99%

Chemical and Charge Imbalance Induced by Radionuclide Decay: Effects on Waste Form Structure

Ginhoven¹,

Jaffe²,

Jiang³

et al. 2011

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SUMMARY ExperimentalIn this section, the experimental results for the Radiation Effects task are summarized. Zr + ion implantation at 550 K was performed and Zr and O atomic concentrations of up to 1.5 at% each in STO were achieved. Effects on the crystal structure, chemistry, and charge states in the implanted STO were studied. A number of analytical methods were employed to characterize the implanted STO, including secondary-ion mass spectroscopy, multiaxial ion-channeling analysis, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Raman spectroscopy. The results show that, in contrast to the observed mobile Sr interstitials in STO, the implanted Zr does not diffuse noticeably during the ion implantation or thermal annealing up to 1423 K. A defect concentration was generated and accumulated in STO during the ion implantation, but the crystal structure was not rendered fully amorphous. Thermal annealing at 1273 K leads to a significant defect recovery at the surface with little recovery occurring at the damage peak, where a modest recovery occurs upon further annealing at 1423 K. The blocking ratio of Zr in STO, as observed along the <001> axis, is ~0.4 and ~0.5 after annealing at 1273 and 1423 K, respectively. Nearly all the implanted Zr species are not located exactly at the original lattice site due to structural distortion. A high density of dislocations was observed in the damage layer, where there were also Zr-containing superlattice structures and voids (or oxygen blisters). Results show that Zr is located at every other Sr site in the superlattice structure. Larger voids and dislocation loops exist beyond the damage layer. There was a minor phase with a tetragonal structure in the damage layer, where the implanted Zr was distributed. The tetragonal phase has the <001> axis parallel to that of the STO host. It survived thermal annealing at 1423 K with only a small decrease in the c value. Changes in chemical states or formation of new chemical bonding were not observed in this study because of the thin implanted layer and limited detection sensitivity. Discussion about the results and a general assessment of the model waste form are also provided in this report.

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Point defect distribution in high-mobility conductiveSrTiO3crystals

Cited by 23 publications

References 34 publications

Persistent Photoconductivity in Strontium Titanate

Persistent Photoconductivity in Strontium Titanate

Performance Improvement of ${\rm HfO}_{2}/{\rm SrTiO}_{3}$ Hetero-Oxide Transistors Using Argon Bombardment

Chemical and Charge Imbalance Induced by Radionuclide Decay: Effects on Waste Form Structure

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