Observation of resonant tunneling in silicon inversion layers

Fowler, A. B.; Timp, G.; Wainer, Jacques; Webb, Richard A.

doi:10.1103/physrevlett.57.138

Cited by 122 publications

(54 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…39 In very short channels (0.5 μιη long and l //m wide) Fowler et a/. 45 have found well-isolated, temperatureindependent (below 100 mK) conductance peaks, which they attributed to resonant tunneling. At very low temperatures a fine structure was observed, some of which was time dependent.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Coulomb-blockade oscillations in disordered quantum wires

et al. 1992

View full text Add to dashboard Cite

The conductance of narrow wires, defined by a split-gate technique in the two-dimensional electron gas in a modulation-doped GaAs-Al^Gai-^As heterostructure, is studied experimentally äs a function of gate voltage, temperature, and magnetic field. Both intentionally (Be doped) and unintentionally disordered wires are investigated. Periodic conductance oscillations äs a function of gate voltage are found in both Systems, in the regime where only a few hundred electrons are present in the wire. The dominant oscillations are very regularly spaced, with a period that is quite insensitive to a strong magnetic field, and persist up to a few kelvin. A strong magnetic field is found to enhance the amplitude of the oscillations up to values approaching e 2 //«. The experimental data are analyzed in terrns of a theory for Coulomb-blockade oscillations in the conductance of a quantum dot in the regime of comparable level spacing Δ-Ε and charging energy e 2 /C, based on the assumed presence of a conductance-limiting segment in the wire. Good agreement with the experiment is obtained for the temperatuie dependence of the oscillations, using physically reasonable parameter values. At low temperatures, a crossover from the classical regime kßT > Δ£ to the quantum regime ksT < AE is found. The appeaiance of additional periodicities and the onset of irregulär oscillations at very low temperatures in some of the wires are attributed to the presence of multiple segments. No magnetoconductance oscillations are observed, in support of the recently predicted Coulomb blockade of the Aharonov-Bohm effect.

show abstract

Section: Discussionmentioning

confidence: 99%

“…Other considerations are necessary to demonstrate t)ic inadequacy of a model based on resonant tunneling of noninteracting electrons. The most important of these are the large activation energy 45 …”

Section: Introductionmentioning

confidence: 99%

Coulomb-blockade oscillations in disordered quantum wires

et al. 1992

View full text Add to dashboard Cite

show abstract

“…Further studies of narrow channel devices (∼ 100 nm) demonstrated a series of reproducible sharp peaks 3 , while later experiments found evidence for resonant tunneling between localised states in the channel. 4,5,6 For sufficiently low impurity concentrations, the overlap between neighbouring localized electron wavefunctions and consequently the hybridisation of their excited states is predicted to be reduced 7 , splitting the single impurity band observed at high concentrations into the ground and excited bands as modeled by Ghazali.…”

mentioning

confidence: 96%

Evidence for multiple impurity bands in sodium-doped silicon MOSFETs

et al. 2006

View full text Add to dashboard Cite

We report measurements of the temperature dependent conductivity in a silicon MOSFET that contains sodium impurities in the oxide layer. We explain the variation of conductivity in terms of Coulomb interactions that are partially screened by the proximity of the metal gate. The study of the conductivity exponential prefactor and the localisation length as a function of gate voltage have allowed us to determine the electronic density of states and has provided arguments for the presence of two distinct bands and a soft gap at low temperature.PACS numbers: 71.23. Cq, 71.55.Gs, 71.55.Jv, 72.15.Rn, 72.20.Ee, 72.80.Ng, 73.20.At, 73.40.Qv Since the invention of the silicon MOSFET, understanding the influence of impurities, especially sodium contamination, on device performance has been a priority and continues to provide a rich system for investigation by experimental and theoretical physicists alike. The electronic properties of sodium doped MOSFETs were first studied by Fowler and Hartstein 1,2 in the 1970s. They reported a single, broad peak in the subthreshold drain current against gate voltage and attributed it to the formation of an impurity band induced by the presence of sodium ions near the Si-SiO 2 interface. Further studies of narrow channel devices (∼ 100 nm) demonstrated a series of reproducible sharp peaks 3 , while later experiments found evidence for resonant tunneling between localised states in the channel. 4,5,6 For sufficiently low impurity concentrations, the overlap between neighbouring localized electron wavefunctions and consequently the hybridisation of their excited states is predicted to be reduced 7 , splitting the single impurity band observed at high concentrations into the ground and excited bands as modeled by Ghazali.8 Increasing the resistivity of the silicon substrate reduces the scattering from acceptors at the Si-SiO 2 interface, allowing the possibility for such a band splitting to be experimentally observed in the transport. In this paper, we will present evidence for the observation of two separate impurity bands with a soft gap, based on analysis of the temperature dependent conductivity below 20 K.The device we used is a MOSFET fabricated on a (100) oriented p-silicon wafer and was subsequently patterned in the circular Corbino geometry to eliminate Hall voltages and possible leakage paths. The effective gate channel length and interior width were respectively 1 µm and 346 µm. A high resistivity wafer (10 4 Ω.cm) provided a background concentration of less than 10 12 cm −3of boron corresponding to a mean distance between impurities of 1 µm. A 35 nm gate oxide was grown at 950• C in a dry, chlorine-free oxygen atmosphere. The phosphorous implanted and aluminium sputtered contacts were highly metallic and Ohmic at all temperatures investigated. Sodium ions were introduced onto the oxide surface by immersing the device in a 10 −7 N solution of high purity sodium chloride (99.999 %) in de-ionised water. The surface of the chip was dried with nitrogen gas and an aluminium gate s...

show abstract

“…The influence of Coulomb repulsion on resonant tunneling through a single twofold spin-degenerate state (for hT <C kT <C e 2 /C) has been studied by Glazman connection with experiments on tunneling through metaloxide-semiconductor structures. 28 To illustrate the generality of the present theory, we show how their special case follows directly from Eq. (4.13).…”

Section: Degenerate Energy Levelsmentioning

confidence: 99%

Theory of Coulomb-blockade oscillations in the conductance of a quantum dot

1991

View full text Add to dashboard Cite

A linear-response theory is developed for resonant tunneling through a quantum dot of small capacitance, in the regime of thermally broadened resonances. The theory extends the classical theory of Coulomb-blockade oscillations by Kulik and Shekhter to the resonant-tunneling regime. Both the cases of negligible and strong inelastic scattering in the quantum dot are considered. Effects from the non-Fermi-Dirac distribution of electrons among the energy levels (occurring when kT is comparable to the level Separation) are fully included. Explicit analytic results are obtained for the periodicity, amplitude, line shape, and activation energy of the conductance oscillations.

show abstract

Observation of resonant tunneling in silicon inversion layers

Cited by 122 publications

References 12 publications

Coulomb-blockade oscillations in disordered quantum wires

Coulomb-blockade oscillations in disordered quantum wires

Evidence for multiple impurity bands in sodium-doped silicon MOSFETs

Theory of Coulomb-blockade oscillations in the conductance of a quantum dot

Contact Info

Product

Resources

About