Electron mobilities in modulation-doped semiconductor heterojunction superlattices

Dingle, R.; Störmer, H. L.; Gossard, A. C.; Wiegmann, W.

doi:10.1063/1.90457

Cited by 1,432 publications

(451 citation statements)

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“…Second, the modulation doping structure affords 2D electron gas transport features. [84] Because the ionized impurity scattering centers are confined in the potential well and blocked by the potential barrier, the car riers are less likely to be scattered. This high carrier mobility derived from the band structure has a slight influence on phonon transport.…”

Section: Strategies From Artificial Superlatticesmentioning

confidence: 99%

Promising Thermoelectric Bulk Materials with 2D Structures

2017

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Given that more than two thirds of all energy is lost, mostly as waste heat, in utilization processes worldwide, thermoelectric materials, which can directly convert waste heat to electricity, provide an alternative option for optimizing energy utilization processes. After the prediction that superlattices may show high thermoelectric performance, various methods based on quantum effects and superlattice theory have been adopted to analyze bulk materials, leading to the rapid development of thermoelectric materials. Bulk materials with two‐dimensional (2D) structures show outstanding properties, and their high performance originates from both their low thermal conductivity and high Seebeck coefficient due to their strong anisotropic features. Here, the advantages of superlattices for enhancing the thermoelectric performance, the transport mechanism in bulk materials with 2D structures, and optimization methods are discussed. The phenomenological transport mechanism in these materials indicates that thermal conductivities are reduced in 2D materials with intrinsically short mean free paths. Recent progress in the transport mechanisms of Bi2Te3‐, SnSe‐, and BiCuSeO‐based systems is summarized. Finally, possible research directions to enhance the thermoelectric performance of bulk materials with 2D structures are briefly considered.

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Section: Strategies From Artificial Superlatticesmentioning

confidence: 99%

Promising Thermoelectric Bulk Materials with 2D Structures

2017

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“…An alternative route to high-mobility 2DEGs is modulation doping, originally developed for III-V heterostructures, 15 leading to devices such as high-electron mobility transistors, 16,17 and scientific discoveries, such as the fractional quantum Hall effect. 18 This approach spatially separates the mobile charge from the ionized dopants by transferring it into an undoped layer.…”

Section: 14mentioning

confidence: 99%

Two-dimensional electron gas in a modulation-doped SrTiO₃/Sr(Ti, Zr)O₃ heterostructure

et al. 2013

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A two-dimensional electron gas (2DEG) in SrTiO 3 is created via modulation doping by interfacing undoped SrTiO 3 with a wider-band-gap material, SrTi 1-x Zr x O 3 , that is doped ntype with La. All layers are grown using hybrid molecular beam epitaxy. Using magnetoresistance measurements, we show that electrons are transferred into the SrTiO 3 , and a 2DEG is formed. In particular, Shubnikov-de Haas oscillations are shown to depend only on the perpendicular magnetic field. Experimental Shubnikov-de Haas oscillations are compared with calculations that assume multiple occupied subbands.

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“…Interface roughness scattering is not important in high quality heterointerfaces at low densities, so the low T mobility is limited by ionised impurity scattering [11,12]. In most twodimensional GaAs systems the carriers are introduced by modulation doping of the AlGaAs, and this modulation doping provides a significant source of remote ionised impurity scattering [13]. Remote ionised impurity scattering can be reduced with the use of large undoped AlGaAs 'spacer' layers between the 2DEG and the modulation doping [14], or eliminated entirely with accumulation mode devices in which the carriers are introduced electrostatically rather than through doping [15].…”

Section: Introductionmentioning

confidence: 99%

Role of background impurities in the single-particle relaxation lifetime of a two-dimensional electron gas

et al. 2009

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We re-examine the quantum τq and transport τt scattering lifetimes due to background impurities in two-dimensional systems. We show that the well-known logarithmic divergence in the quantum lifetime is due to the non-physical assumption of an infinitely thick heterostructure, and demonstrate that the existing non-divergent multiple scattering theory can lead to unphysical quantum scattering lifetimes in high quality heterostructures. We derive a non-divergent scattering lifetime for finite thickness structures, which can be used both with lowest order perturbation theory and the multiple scattering theory. We calculate the quantum and transport lifetimes for electrons in generic GaAsAlGaAs heterostructures, and find that the correct 'rule of thumb' to distinguish the dominant scattering mechanisms in GaAs heterostructures should be τt/τq 10 for background impurities and τt/τq 10 for remote impurities. Finally we present the first comparison of theoretical results for τq and τt with experimental data from a GaAs 2DEG in which only background impurity scattering is present. We obtain excellent agreement between the calculations and experimental data, and are able to extract the background impurity density in both the GaAs and AlGaAs regions.

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Electron mobilities in modulation-doped semiconductor heterojunction superlattices

Cited by 1,432 publications

References 10 publications

Promising Thermoelectric Bulk Materials with 2D Structures

Promising Thermoelectric Bulk Materials with 2D Structures

Two-dimensional electron gas in a modulation-doped SrTiO₃/Sr(Ti, Zr)O₃ heterostructure

Role of background impurities in the single-particle relaxation lifetime of a two-dimensional electron gas

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Electron mobilities in modulation-doped semiconductor heterojunction superlattices

Cited by 1,432 publications

References 10 publications

Promising Thermoelectric Bulk Materials with 2D Structures

Promising Thermoelectric Bulk Materials with 2D Structures

Two-dimensional electron gas in a modulation-doped SrTiO3/Sr(Ti, Zr)O3 heterostructure

Role of background impurities in the single-particle relaxation lifetime of a two-dimensional electron gas

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Two-dimensional electron gas in a modulation-doped SrTiO₃/Sr(Ti, Zr)O₃ heterostructure