Anomalous change in dielectric constant of CaCu3Ti4O12 under violet-to-ultraviolet irradiation

Masingboon, Chivalrat; Eknapakul, Tanachat; Suwanwong, Sanit; Buaphet, P.; Nakajima, Hideki; Mo, S.-K.; Thongbai, Prasit; King, P. D. C.; Maensiri, Santi; Meevasana, W.

doi:10.1063/1.4807741

Cited by 25 publications

(16 citation statements)

References 36 publications

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“…2(a)). It was found that the O 2p state located at a binding energy around 6-8 eV was consistent with other metal oxides 25,26,34 indicating a good electrical contact between our sample and a sample holder. A counterintuitive shift of the O 2p state to lower binding energy was initially observed by the first doping condition (5 min of UV light exposure) as illustrated by the red spectrum in Fig.…”

Section: Resultssupporting

confidence: 84%

“…1(b,f)) which could be described by the photogeneration of charge carriers. However, since the capacitance measured here does not instantly recover back to its original value when the irradiation is off, such changes are attributed to the creation of a thin conductive layer upon the insulating bulk referred to as a quantum-confined electron gas which is related to the creation of oxygen vacancies induced by light irradiation 26,31,32 .…”

Section: Resultsmentioning

confidence: 79%

“…Alternatively, carrier densities on metal oxide surfaces can be controlled by the creation of oxygen vacancy states induced by light irradiation [22][23][24][25] . Recently, the capacitance enhancement induced by surface charge accumulation has been reported on CaCu 3 Ti 4 O 12 26 . This is similar to the case of applying electric field (i. e. introduction of the quantum conductive interfaces) which might indicate the analogous microscopic origin.…”

Section: Openmentioning

confidence: 99%

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Interplay of negative electronic compressibility and capacitance enhancement in lightly-doped metal oxide Bi0.95La0.05FeO3 by quantum capacitance model

Nathabumroong

Eknapakul

Jaiban

et al. 2020

Sci Rep

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Light-sensitive capacitance variation of Bi 0.95 La 0.05 feo 3 (BLfo) ceramics has been studied under violet to UV irradiation. The reversible capacitance enhancement up to 21% under 405 nm violet laser irradiation has been observed, suggesting a possible degree of freedom to dynamically control this in high dielectric materials for light-sensitive capacitance applications. By using ultraviolet photoemission spectroscopy (UpS), we show here that exposure of BLfo surfaces to UV light induces a counterintuitive shift of the o 2p valence state to lower binding energy of up to 243 meV which is a direct signature of negative electronic compressibility (NEC). A decrease of BLFO electrical resistance agrees strongly with the UpS data suggesting the creation of a thin conductive layer on its insulating bulk under light irradiation. By exploiting the quantum capacitance model, we find that the negative quantum capacitance due to this NEC effect plays an important role in this capacitance enhancement

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Section: Resultssupporting

confidence: 84%

Section: Resultsmentioning

confidence: 79%

Section: Openmentioning

confidence: 99%

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Interplay of negative electronic compressibility and capacitance enhancement in lightly-doped metal oxide Bi0.95La0.05FeO3 by quantum capacitance model

Nathabumroong

Eknapakul

Jaiban

et al. 2020

Sci Rep

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“…Note that the change in resistance under UV irradiation of titanium oxide compounds already finds various applications as previously reported, e.g. UV detector [16], lightsensitive capacitor [17][18][19] and enhanced magnitism [20]. In the oxygen-vacancy scenario, the resistance of an insulating sample will become lower when more of oxygen vacancy is created on the SrTiO 3 surface; on the other hand, if the vacancies are healed with oxygen exposure, the resistance should become higher again.…”

Section: Resultsmentioning

confidence: 99%

The dynamics of ultraviolet-induced oxygen vacancy at the surface of insulating SrTiO 3 (0 0 1)

Suwanwong

Eknapakul

Rattanachai

et al. 2015

Applied Surface Science

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A c c e p t e d M a n u s c r i p t Highlights (for review) -The dynamics of UV-induced oxygen vacancy is studied from the change of surface resistance.-The formation of 2DEG at the insulating surface of SrTiO 3 is confirmed by ARPES.-The UV-induced change in resistance responds differently to oxygen/gas exposure.-The behavior of resistance recovery suggests an alternative method of low-pressure sensing.Page 2 of 5 A c c e p t e d M a n u s c r i p t The effect of ultra-violet (UV) irradiation on the electronic structure and the surface resistance of an insulating SrTiO3(001) crystal is studied in this work. Upon UV irradiation, we shows that the two-dimensional electron gas (2DEG) emerges at the insulating SrTiO3 surface and there is a pronounced change in the surface resistance. By combining the observations of the change in valance band and the resistance change under different environments of gas pressure and gas species, we find that UV-induced oxygen vacancies at the surface plays a major role in the resistance change. The dynamic of the resistance change at different oxygen pressures also suggests an alternative method of low-pressure sensing.

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“…CCTO polycrystalline ceramics can also exhibit non-Ohmic properties [12-20]. These two properties give CCTO potential for applications in capacitor and varistor devices, respectively.…”

Section: Introductionmentioning

confidence: 99%

Dramatically enhanced non-Ohmic properties and maximum stored energy density in ceramic-metal nanocomposites: CaCu3Ti4O12/Au nanoparticles

et al. 2013

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Non-Ohmic and dielectric properties of a novel CaCu3Ti4O12/Au nanocomposite were investigated. Introduction of 2.5 vol.% Au nanoparticles in CaCu3Ti4O12 ceramics significantly reduced the loss tangent while its dielectric permittivity remained unchanged. The non-Ohmic properties of CaCu3Ti4O12/Au (2.5 vol.%) were dramatically improved. A nonlinear coefficient of ≈ 17.7 and breakdown electric field strength of 1.25 × 104 V/m were observed. The maximum stored energy density was found to be 25.8 kJ/m3, which is higher than that of pure CaCu3Ti4O12 by a factor of 8. Au addition at higher concentrations resulted in degradation of dielectric and non-Ohmic properties, which is described well by percolation theory.

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Anomalous change in dielectric constant of CaCu3Ti4O12 under violet-to-ultraviolet irradiation

Cited by 25 publications

References 36 publications

Interplay of negative electronic compressibility and capacitance enhancement in lightly-doped metal oxide Bi0.95La0.05FeO3 by quantum capacitance model

Interplay of negative electronic compressibility and capacitance enhancement in lightly-doped metal oxide Bi0.95La0.05FeO3 by quantum capacitance model

The dynamics of ultraviolet-induced oxygen vacancy at the surface of insulating SrTiO 3 (0 0 1)

Dramatically enhanced non-Ohmic properties and maximum stored energy density in ceramic-metal nanocomposites: CaCu3Ti4O12/Au nanoparticles

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