Dielectric response function for a quasi-one-dimensional semiconducting system

Lee, Johnson; Spector, Harold N.

doi:10.1063/1.334816

Cited by 106 publications

(30 citation statements)

References 13 publications

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“…͑27͒ at k ϭ2k F is divergent and is to be replaced [2][3][4] with the one at a low temperature (k B TӶE F ):…”

Section: B Density Of Statesmentioning

confidence: 99%

“…The quasi-one-dimensional electron gas ͑1DEG͒ in the wire is generally violently affected by disorder arising from impurity doping. The disorder has been shown to lead to remarkable changes in the observable properties of the wire, e.g., the electron mobility [1][2][3][4][5] and the density of states ͑DOS͒. [6][7][8][9] It should be mentioned that all existing theories 1-9 of the disorder effect from impurity doping in QWR's were established by assuming that the ionized impurities are absolutely randomly distributed in the sample.…”

Section: Introductionmentioning

confidence: 99%

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Effect of impurity correlation in modulation-doped quantum wires

2001

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A theory is given of the electronic properties of modulation-doped quantum wires which undergo a thermal treatment, taking into account the Coulomb interaction among ionized impurities in the sample preparation. It is pointed out that the correlation among impurities weakens their field and is enhanced when elevating the doping level, lowering the freezing temperature for impurity diffusion, and reducing the size of the impurity system. The screening of the ionic correlation by charge carriers in the sample growth is of minor importance. In the limiting case of a one-dimensional impurity system, the correlation may totally suppress the random field at any doping level, so that a finite electron mobility is governed by other scattering mechanisms than impurity doping, e.g., interface roughness and alloying. It is found that the ionic correlation changes the electron mobility of quantum wires as regards not only its magnitude but its dependence on the doping conditions as well. For impurity systems of a small size, the mobility may be increased by up to more than one order of magnitude at a doping level of 10 6 cm Ϫ1 .

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“…͑27͒ at k ϭ2k F is divergent and is to be replaced [2][3][4] with the one at a low temperature (k B TӶE F ):…”

Section: B Density Of Statesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of impurity correlation in modulation-doped quantum wires

2001

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“…Much work has been devoted to the study of hydrogenic impurity states in these systems [6 -33]. Binding energy calculations for hydrogenic impurities in quantum wells (QWs) [6 -8], quantum well wires (QWWs) [9][10][11][12][13][14][15][16][17][18][19][20][21] and quantum dots (QDs) [22][23][24] have been performed. It is found that when the dimensions of the system are reduced, the quantum size becomes clear and the effective strength of the coulomb interaction increases.…”

Section: Introductionmentioning

confidence: 99%

Electric field effect on the binding energy of a non‐hydrogenic donor impurity in a cylindrical cross‐sectional quantum well wire

Ulas

Cicek

Dalgic

2004

Physica Status Solidi (b)

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The effect of an electric field on the non-hydrogenic binding energy of a shallow donor impurity in a cylindrical cross-sectional GaAs-(Ga,Al)As quantum well wire (QWW) was investigated. Within the effective mass approximation, the non-hydrogenic binding energy of the donor impurity was calculated by a variational method as a function of the wire radius, donor impurity position and applied electric field. The results show that the non-hydrogenic binding energy of the donor impurity located around the centre is larger than that of the hydrogenic binding energy. The difference in binding energy of an on-centre shallow donor impurity in the two regimes increases more rapidly with decreasing QWW radius than for other impurity positions. It has been found that the sensitivity of the donor binding energies to the applied electric field in both regimes is almost the same.

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“…The bare potential in NWs is screened due to the presence of free carriers. The quasi 1D screening function (q, 0) can be calculated using the self-consistent procedure outlined by Lee and Spector [11]; we have included the effect of the dielectric mismatch to their screening theory. At low temperatures, the carriers contributing to transport are predominantly those at the Fermi level, and the momentum change upon scattering is q ≈ 2k F , where k F is the Fermi wavevector.…”

Section: Arxiv:09062371v1 [Cond-matmes-hall] 12 Jun 2009mentioning

confidence: 99%

Tailoring the carrier mobility of semiconductor nanowires by remote dielectrics

Konar

Jena

2007

Journal of Applied Physics

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The dielectric environment of thin semiconductor nanowires can affect the charge transport properties inside the wire. In this work, it is shown that Coulomb impurity scattering inside thin nanowires can be damped strongly by coating the wire with a high-κ dielectric. This will lead to an increase in the mobility of free charges inside the wire.PACS numbers: 73.50.-h Remarkable advances in crystal growth technology have recently enabled the fabrication of a variety of freestanding semiconductor nanostructures such as 0-dimensional (0D) nanocrystal quantum dots, 1D nanowires (NWs) and nanotubes, and 2D nanomembranes and graphene. Charge transport properties in such nanostructures is being intensively investigated, in the hope that they might find usage in electronic and optical devices in the future. These 'bottom-up' nanostructures differ from the more extensively studied epitaxial nanostructures created by heterostructure bandgap engineering in one crucial aspect. The dielectric environment of epitaxial nanostructures is essentially the same as the semiconducting region (dielectric constant s ) where electrons and holes reside. However, for bottom-up nanostructures, the dielectric environment ( e ) can be modified after growth. This feature offers a novel tool to engineer interactions between carriers and/or impurities by environment-mediated Coulomb interactions.The effect of the dielectric environment on charge transport properties of 'bottom-up' nanostructures has not received much attention, as compared to its effect on optical properties [1]. Recent work [2] has shown that in 2D nanomembranes the electron mobility can be increased by 1-2 orders of magnitude by coating them with a high-κ dielectric material. The purpose of this work is to investigate the effect of the dielectric environment on electron transport in semiconductor nanowires. Semiconductor NWs can now be grown with diameters of a few nanometers, which is smaller than the thermal de Broglie wavelength of the carriers, while their lengths can exceed few micrometers. At these length scales, the reduced density of states due to quantum confinement is expected to suppress scattering, and lead to high carrier mobilities [3]. Recent experiments [4] have demonstrated improved carrier mobilities in Ge/Si nanowire field-effect transistors coated with high-κ (HfO 2 ) dielectrics.In early work on carrier transport of 1D semiconductor nanowires [5,6], the effect of dielectric mismatch on transport properties was not investigated. Vagner and Mosko showed in their treatment of a 1D electron gas confined in a freestanding 2D membrane that the dielectric mismatch leads to a large decrease in mobility if the structure is freestanding [7]. In this letter, we show that FIG. 1: Calculated Coulomb potential contours due to a point charge inside a nanowire for three different dielectric environments: e = 1, 11, 100, s = 11. The potential is strongly enhanced for freestanding wires ( e = 1), whereas it is strongly damped for a high-κ coating.for 1D nanowires, the ...

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Dielectric response function for a quasi-one-dimensional semiconducting system

Cited by 106 publications

References 13 publications

Effect of impurity correlation in modulation-doped quantum wires

Effect of impurity correlation in modulation-doped quantum wires

Electric field effect on the binding energy of a non‐hydrogenic donor impurity in a cylindrical cross‐sectional quantum well wire

Tailoring the carrier mobility of semiconductor nanowires by remote dielectrics

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