Effect of size on dielectric constant for low dimension materials

Tian, Mei; Li, M.; Li, J.C.

doi:10.1016/j.physb.2010.11.034

Cited by 12 publications

(6 citation statements)

References 30 publications

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“…So, with larger grain size, the number of grains/unit volume decreases, resulting in a lower dielectric constant [10]. On the other hand, surface modi cation of the conducting grains by poorly conducting extract molecules, i.e., modi cation of the grain boundary surfaces will change the dielectric constant of the modi ed ZnO nanoparticles which depends on the polarizable bonds on the surface manifested through their shape and size [53]. These may explain why the dielectric constant values at steady temperatures in the low frequency range change with the changing particle size…”

Section: Dielectric Constantmentioning

confidence: 99%

“…Dielectric constant of bulk ZnO is less than the ZnO nanoparticles [52]. Numerous theoretical models are developed to study the size-dependence of dielectric constant of semiconductor nanostructures and in the nanometric range, with different interface conditions and shape of nanocrystals, dielectric constant can increase or decrease with the particles size change [53][54][55][56][57][58][59][60]. For ZnO, the crystal defects created during synthesis affect the dielectric constant at low frequencies signi cantly [52,61,62].…”

Section: Introductionmentioning

confidence: 99%

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Study on the dielectric property, ac conductivity and electric modulus of pristine and green synthesized ZnO nanoparticles

Sarkar¹,

Kundu²,

Bhattacharjee³

2023

Preprint

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We report the results obtained on the studies made for temperature and frequency dependence of the dielectric constant, loss and ac conductivity for pristine and green-synthesized ZnO nanoparticles as well as investigations of their electric modulus. Frequency-dependent dielectric studies are carried out with the pelletized samples of ZnO at different temperatures. At lower frequencies (< 1 kHz) and at higher temperatures the ZnO nanoparticles have giant dielectric constant values (~ 4x104), and such a temperature-dependent giant dielectric constant has not been seen earlier, to our knowledge, in any pristine ZnO nanoparticle. In the lower frequency region and below 100○C the nature of temperature dependence of the dielectric constant for pristine ZnO is in contrast with that observed for the green-synthesized ZnO nanoparticles. This anomalous temperature dependence of dielectric constant may be correlated with combined effect of the in-plane and out of plane thermal-expansion coefficients of ZnO. A temperature-dependent poly-dispersive relaxation mechanism in these materials have been observed. The electrical conduction mechanism is found to be significantly modulated by the use of the extract. Electric modulus study reveals that the electrical conduction and dielectric polarization follow the same mechanism in these ZnO nanoparticles. The dependences of the dielectric constant, dielectric loss, conductivity and polarization mechanisms observed in the synthesized ZnO nanoparticles are envisaged as the signatures of the effective control of the flour extract on the crystal growth and formation of grain boundaries. A plausible growth mechanism of the ZnO nanoparticles in presence of the flower extract containing phytochemicals is also provided.

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Section: Dielectric Constantmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Study on the dielectric property, ac conductivity and electric modulus of pristine and green synthesized ZnO nanoparticles

Sarkar¹,

Kundu²,

Bhattacharjee³

2023

Preprint

View full text Add to dashboard Cite

show abstract

“…Numerous theoretical models are developed to study the size dependence of dielectric constant of these semiconductor nanostructures and in the nanometric range, with different interface conditions and shape of nanocrystals, dielectric constant can increase or decrease with the particles size change. [58][59][60][61][62][63][64][65] Though it is now established that the plant extracts meaningfully control the size and energy band of the ZnO NPs, there are only few reports on the dielectric studies of the green-synthesized ZnO NPs. [5,[66][67][68][69][70] Recently, we reported green-synthesized ZnO NPs (17.5-23.3 nm) [71] using Tabernaemontana divaricata flower extract (TFE), where the extract efficiently modifies the structure, optical property, and defect levels of the NPs.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Dielectric Property, AC Conductivity, and Electric Modulus Studies of Pristine and Green‐Synthesized ZnO Nanoparticles

Sarkar,

Kundu,

Bhattacharjee

2024

Physica Status Solidi (a)

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Frequency‐dependent dielectric constant and dielectric loss of pristine and green‐synthesized (using Tabernaemontana divaricata flower extract) ZnO nanoparticles (NPs) are studied at different temperatures. Below 1 kHz frequency and at temperatures above 100 °C, ZnO NPs have giant dielectric constant values (≈3 × 104). At lower frequencies and at/below 100 °C, the nature of temperature dependence of dielectric constant for pristine and green‐synthesized ZnO NPs are reversed, and this anomalous temperature dependence is correlated with the in‐plane and out‐of‐plane thermal expansions of ZnO. A temperature‐dependent poly‐dispersive relaxation mechanism in ZnO has been observed. The electrical conduction mechanism is found to be significantly modulated by the use of flower extract. The electric modulus study suggests similar mechanism of electrical conduction and dielectric polarization followed in these materials. A plausible growth mechanism of the ZnO NPs in presence of the flower extract is explored. Variations in the dielectric constant, dielectric loss, conductivity, and polarization mechanisms of the ZnO NPs are understood as signatures of the capping effect of the phytochemicals present in the flower extract on the crystal growth and formation of grain boundaries.

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“…Strictly speaking, in the case of QDs, a refractive index can be considered only as an empirical parameter since a refractive index is a macroscopic measurable quantity. At the same time, optical properties of low-dimension materials strongly depend on the dielectric constant, 5 which is simply the square of the complex refractive index in nonmagnetic macroscopic media. In some cases, refractive index or dielectric constant profiles in waveguides can be reconstructed from measurements of spatial distributions, such as near-field or far-field patterns, of waveguide modes.…”

Section: Introductionmentioning

confidence: 99%

Refractive index of laser active region based on InAs/InGaAs quantum dots

et al. 2013

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The effective refractive index of the active region of 1.3 μm edge-emitting tilted wave lasers based on InAs/InGaAs self-assembled quantum dots by the analysis of the far-field pattern is investigated. The obtained values of 3.485 and 3.487 in the operating lasers and in the cold waveguides, respectively, are well comparable with the refractive index of bulk InAs at corresponding wavelength. Downloaded From: http://nanophotonics.spiedigitallibrary.org/ on 09/29/2016 Terms of Use: http://spiedigitallibrary.org/ss/termsofuse.aspx Gordeev et al.: Refractive index of laser active region based on InAs/InGaAs quantum dots Downloaded From: http://nanophotonics.spiedigitallibrary.org/ on 09/29/2016 Terms of Use: http://spiedigitallibrary.org/ss/termsofuse.aspx Gordeev et al.: Refractive index of laser active region based on InAs/InGaAs quantum dots Downloaded From: http://nanophotonics.spiedigitallibrary.org/ on 09/29/2016 Terms of Use: http://spiedigitallibrary.org/ss/termsofuse.aspx Gordeev et al.: Refractive index of laser active region based on InAs/InGaAs quantum dots Downloaded From: http://nanophotonics.spiedigitallibrary.org/ on 09/29/2016 Terms of Use: http://spiedigitallibrary.org/ss/termsofuse.aspx Gordeev et al.: Refractive index of laser active region based on InAs/InGaAs quantum dots Downloaded From: http://nanophotonics.spiedigitallibrary.org/ on 09/29/2016 Terms of Use: http://spiedigitallibrary.org/ss/termsofuse.aspx Gordeev et al.: Refractive index of laser active region based on InAs/InGaAs quantum dots

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Effect of size on dielectric constant for low dimension materials

Cited by 12 publications

References 30 publications

Study on the dielectric property, ac conductivity and electric modulus of pristine and green synthesized ZnO nanoparticles

Study on the dielectric property, ac conductivity and electric modulus of pristine and green synthesized ZnO nanoparticles

Dielectric Property, AC Conductivity, and Electric Modulus Studies of Pristine and Green‐Synthesized ZnO Nanoparticles

Refractive index of laser active region based on InAs/InGaAs quantum dots

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