Spontaneous polarization effects in nanoscale wurtzite structures

Yamanaka, T.; Dutta, Mitra; Stroscio, Michael A.

doi:10.1007/s10825-006-0115-5

Cited by 6 publications

(3 citation statements)

References 13 publications

(15 reference statements)

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“…In our view, the excellent agreement of these measured I -V curves with the modelled I -V curves, based on the steady-state current analysis [3], provides additional support for the phenomenon of current transport in DNA [5].…”

Section: Resultssupporting

confidence: 69%

Comparison of calculated and measured I–V curves for DNA

et al. 2008

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Cohen et al. have reported experimental observations of current passing through the dsDNA molecules using a metal-covered atomic force microscope (AFM) tip; the molecules are chemically connected to a metal substrate at one end and to a gold nanoparticle (GNP) at the opposite end. They have presented evidence for charge transport through dsDNA molecules of a complex sequence, 26 bp long, characterized by S-shaped current-voltage (I -V ) curves. In this paper, theoretical calculations giving excellent agreement with the results of Cohen et al. are obtained using the formalism of Datta et al.

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Section: Resultssupporting

confidence: 69%

Comparison of calculated and measured I–V curves for DNA

et al. 2008

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“…Then, we extend this approach to calculate the P sp values of nanoscale quantum well or thin film structures consisting of differing numbers of monolayers which differ from that of bulk. The underlying causes for P sp to differ for such nanoscale structures and for the bulk is non-integer number of elementary lattices within the overall structure and surface/interface charges, an effect which is negligible in bulk values but can have a large effect on the P sp values in small nanoscale lattices [ 6 , 7 , 8 ]. This effect of the P sp deviation of nanostructures from that of bulk and the multiplication of this effect due to how the bonds of the surface atom terminate will become clear both in theory and mathematically as we continue.…”

Section: Introductionmentioning

confidence: 99%

Spontaneous Polarization Calculations in Wurtzite II-Oxides, III-Nitrides, and SiC Polytypes through Net Dipole Moments and the Effects of Nanoscale Layering

2021

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Herein, the spontaneous polarization in crystals with hexagonal symmetry are calculated as a function of the number of monolayers composing a nanostructure by adding the dipole moments for consecutive units of the nanostructure. It is shown that in the limit of a large numbers of monolayers that the spontaneous polarization saturates to the expected bulk value of the spontaneous polarization. These results are relevant to understanding the role of the built-in spontaneous polarizations in a variety of nanostructures since these built-in polarizations are generally quite large, on the order of 1 × 108 to 1 × 1010 V/m. Using these formulations, we come to the prediction that small nanolayered structures are theoretically capable of having larger spontaneous polarizations than their bulk counterparts due to how the dipole moments of the anions and cations within a wurtzite lattice cancel out with one another more in larger structures.

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“…At present there are two major challenges in achieving higher efficiency with wurtzite III-nitride semiconductors. First, the presence of spontaneous polarization causing a built-in potential of up to a few MV cm −1 [10]; this potential alters the potential inside the quantum well of the active region of LEDs causing reduced efficiency of emission due to a reduction in the overlap of the electron and hole wavefunction (this phenomenon is better known as the quantum stark effect) [11]. Second, crystal defects arise due to growth on lattice mismatched substrates like SiC, GaAs or sapphire, which have been explored due to the high cost of GaN substrates [12].…”

Section: Introductionmentioning

confidence: 99%

Electron–optical-phonon scattering rates in cubic group III-nitride crystals: path-integral corrections to Fermi golden rule matrix elements

Singh¹,

Dutta²,

Stroscio³

2021

Semicond. Sci. Technol.

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III-nitride semiconductors with a cubic crystal structure have shown promise in enhancing efficiency in photonic and optoelectronic applications. The recent interest in cubic III-nitrides has arisen due to the inability to realize enhanced efficiency in optoelectronic applications of the wurtzite phase due to spontaneous polarization effects, crystal defects due to growth on lattice mismatched substrates, and also due to the requirement to fabricate normally-off transistors for high-mobility transistors. Cubic III-nitride materials are characterized by the strong coupling of carriers to optical phonons in which the standard perturbative approach—based on first order perturbation theory—breaks down. In this paper we determine the necessary corrections to the Fermi golden rule electron–optical-phonon matrix elements for selected cubic III-nitrides via the nonperturbative Thornber–Feynman path-integral techniques. Specifically, we report electron transport parameters such as the threshold electric field, threshold velocity, mobility and runaway length for BN, AlN, GaN and InN. 72.10.Di, 72.15.Lh, 72.80.Ey.

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Spontaneous polarization effects in nanoscale wurtzite structures

Cited by 6 publications

References 13 publications

Comparison of calculated and measured I–V curves for DNA

Comparison of calculated and measured I–V curves for DNA

Spontaneous Polarization Calculations in Wurtzite II-Oxides, III-Nitrides, and SiC Polytypes through Net Dipole Moments and the Effects of Nanoscale Layering

Electron–optical-phonon scattering rates in cubic group III-nitride crystals: path-integral corrections to Fermi golden rule matrix elements

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