Schottky-barrier tunneling spectroscopy for the electronic subbands of a δ-doping layer

Zachau, M.; Koch, F.; Ploog, K.; Roentgen, P.; Beneking, H.

doi:10.1016/0038-1098(86)90066-9

Cited by 48 publications

(13 citation statements)

References 6 publications

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“…On the contrary, as the vertical impurity segregation increases, the VS decreases significantly. As a result measuring the VS experimentally, such as by using Schottky-barrier tunneling spectroscopy, 18,20,54,55 can be used to determine the degree of vertical dopant diffusion.…”

Section: The Effect Of Disorder In the Si:p δ Layermentioning

confidence: 99%

Electronic structure of realistically extended atomistically resolved disordered Si:Pδ-doped layers

et al. 2011

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The emergence of scanning tunneling microscope (STM) lithography and low temperature molecular beam epitaxy (MBE) opens the possibility of creating scalable donor based quantum computing architectures. In particular, atomically precise Si:P monolayer structures (δ-doped layers) serve as crucial contact regions and in-plane gates in single impurity devices. In this paper we study highly confined δ-doped layers to explain the disorder in the P dopant placements in realistically extended systems. The band structure is computed using the tight-binding formalism and charge-potential self-consistency. The exchange-correlation corrected impurity potential pulls down subbands below the silicon valley minima to create impurity bands. Our methodology is benchmarked and validated against other theoretical methods for small ordered systems. The doping density is shown to linearly control the impurity bands. Disorder within the Si:P δ-doped layer is examined using an extended domain to describe the effects of experimentally unavoidable randomness through explicitly disordered dopant placement. Disorder in the δ-doped layer breaks the symmetry in the supercell and creates band splitting in every subband. Vertical segregation of dopants is shown to dramatically reduce valley splitting (VS). Such VS can be used as a measure of ideality of the fabricated Si:P δ-doped layer. Although the resulting disorder induces density of states fluctuations, this theoretical analysis shows that δ-doped layers can serve as quasimetallic 2D electron sources even in the presence of strong nonidealities.

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Section: The Effect Of Disorder In the Si:p δ Layermentioning

confidence: 99%

Electronic structure of realistically extended atomistically resolved disordered Si:Pδ-doped layers

et al. 2011

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“…3 are due to the zero-bias anomaly ͑at Ϸ0 V͒ and phonon-assisted tunneling ͑at Ϸ Ϯ 36 mV͒. [1][2][3]5 We note here that, generally speaking, the positions of the subband bottoms at zero bias do not correspond exactly to the bias points ͑ϫe, here e is the electron charge͒ of the minima in the spectrum. The deviation in our structures is typically ϳ10% of the bias points ͑ϫe͒ of the minima: the subbands in the channel are shifting slightly with respect to the channel Fermi level, when the bias is changing.…”

Section: B Theoretical Calculationsmentioning

confidence: 83%

“…There are two main reasons that have made the observation of the above effects possible. First, one can apply the tunnel-spectroscopy measurement technique 1,8,9 to such structures. The tunnel spectroscopy has the advantage that one can access both the occupied and empty subbands, in contrast to the usual magnetotransport measurements of the 2D electron systems ͑see, e.g., Ref.…”

Section: Introductionmentioning

confidence: 99%

Strong inhomogeneity of the tunnel Schottky structures withδ-doped two-dimensional channels at large bias

2010

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The electron transport in the tunnel Al/GaAs Schottky structures with two-dimensional ␦-doped channels is investigated both experimentally and theoretically. We observe experimentally strong inhomogeneity and "freezing" of the potential profile along the channel at large biases. Also, the total current saturates at large biases and the differential resistance shows a characteristic nonmonotonous behavior. A theoretical model for the structures is developed. It is in quantitative agreement with the measurements. The model explains the observed features by the channel depletion and the decrease of its conductivity with bias. Our measurements and theoretical calculations indicate that a local impurity-density-induced transition into insulator state is taking place in our structures, when the electron concentration in the channel is still relatively high ͑Ϸ3 ϫ 10 11 cm −2 ͒. We identify the poor conductivity of the locally depleted part of the channel as the bottleneck leading to the current saturation and to appearance of the other features mentioned above.

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“…In general, the doping of the interface results in a creation of a potential well close to the barrier. 42,43,44 Even if there is no well in equilibrium, at high forward bias when less electrons need to be depleted from the semiconductor, the well creation is inevitable. In Sec.…”

Section: Spin Transport Through the Schottky Barriermentioning

confidence: 99%

Electrical expression of spin accumulation in ferromagnet/semiconductor structures

Cywinski,

Dery,

Dalal

et al. 2007

Preprint

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We treat the spin injection and extraction via a ferromagnetic metal/semiconductor Schottky barrier as a quantum scattering problem. This enables the theory to explain a number of phenomena involving spin-dependent current through the Schottky barrier, especially the counter-intuitive spin polarization direction in the semiconductor due to current extraction seen in recent experiments. A possible explanation of this phenomenon involves taking into account the spin-dependent inelastic scattering via the bound states in the interface region. The quantum-mechanical treatment of spin transport through the interface is coupled with the semiclassical description of transport in the adjoining media, in which we take into account the in-plane spin diffusion along the interface in the planar geometry used in experiments. The theory forms the basis of the calculation of spin-dependent current flow in multi-terminal systems, consisting of a semiconductor channel with many ferromagnetic contacts attached, in which the spin accumulation created by spin injection/extraction can be efficiently sensed by electrical means. A three-terminal system can be used as a magnetic memory cell with the bit of information encoded in the magnetization of one of the contacts. Using five terminals we construct a reprogrammable logic gate, in which the logic inputs and the functionality are encoded in magnetizations of the four terminals, while the current out of the fifth one gives a result of the operation.

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Schottky-barrier tunneling spectroscopy for the electronic subbands of a δ-doping layer

Cited by 48 publications

References 6 publications

Electronic structure of realistically extended atomistically resolved disordered Si:Pδ-doped layers

Electronic structure of realistically extended atomistically resolved disordered Si:Pδ-doped layers

Strong inhomogeneity of the tunnel Schottky structures withδ-doped two-dimensional channels at large bias

Electrical expression of spin accumulation in ferromagnet/semiconductor structures

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