Effects of localised states and interparticle interactions on the STM/STS and AFM nanostructure diagnostics

Maslova, N. S.; Moiseev, Yu. N.; Panov, V. I.; Savinov, S. Yu.

doi:10.1070/pu1995v038n02abeh001467

Cited by 5 publications

(2 citation statements)

References 4 publications

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“…For nanoscale junctions the local density of states in the contact area is strongly altered by tipsample interactions. These interactions result in considerable shifts of the allowed energy levels, where deep lying levels may be driven through the Fermi level [13][14][15]. Localized states can not only be connected with the sample surface [6], but also appear at the tip apex [16].…”

Section: Introductionmentioning

confidence: 99%

Scanning tunneling microscopy and spectroscopy at low temperatures of the (110) surface of Te-doped GaAs single crystals

et al. 1999

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We have performed voltage dependent imaging and spatially resolved spectroscopy on the (110) surface of Te doped GaAs single crystals with a low temperature scanning tunneling microscope (STM). A large fraction of the observed defects are identified as Te dopant atoms which can be observed down to the fifth subsurface layer. For negative sample voltages, the dopant atoms are surrounded by Friedel charge density oscillations. Spatially resolved spectroscopy above the dopant atoms and above defect free areas of the GaAs (110) surface reveals the presence of conductance peaks inside the semiconductor band gap. The appearance of the peaks can be linked to charges residing on states which are localized within the tunnel junction area. We show that these localized states can be present on the doped GaAs surface as well as at the STM tip apex.

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Section: Introductionmentioning

confidence: 99%

Scanning tunneling microscopy and spectroscopy at low temperatures of the (110) surface of Te-doped GaAs single crystals

et al. 1999

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“…This is generally caused by the following reasons. (i) For system sizes comparable to the atomic scale, the local density of states in the contact area can be strongly altered by the tunneling current (tip-sample interaction), resulting in the appearance of additional localized states near the Fermi level [2][3][4][5]. (ii) Individual localized states start to dominate the tunneling current, because the radii of the localized states become comparable to the area of the contact size [6].…”

mentioning

confidence: 99%

Influence of resonant tunneling on the imaging of atomic defects on InAs(110) surfaces by low-temperature scanning tunneling microscopy

Depuydt

Maslova

Panov

et al. 1998

Applied Physics A: Materials Science & Processing

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We have used a low-temperature scanning tunneling microscope (STM) to study the surface of heavily doped semiconductor InAs crystals. The crystals are cleaved in situ along the (110) plane. Apart from atomically flat areas, we also observe two major types of atomic-scale defects which can be identified as S dopant atoms and As vacancies, respectively. The strong bias voltage dependence of the STM image of the impurities can be explained in terms of resonant tunneling through localized states which are present near the impurity.With the advent of the scanning tunneling microscope (STM) and the decrease of system sizes down to the nanometer scale, experimental results can often no longer be interpreted in terms of the standard model for STM imaging [1], generally for the following reasons.-For system sizes comparable to the atomic scale, the local density of states in the contact area can be greatly altered by the tunneling current (tip-sample interaction), resulting in the appearance of additional localized states near the Fermi level [2-5]. -Individual localized states start to dominate the tunneling current, because the radii of the localized states become comparable to the area of the contact size [6]. -In the presence of localized states, the finite relaxation rate of the nonequilibrium electrons has to be taken into account, especially at low temperatures where the relaxation rate may become smaller than the tunneling rate [7]. In a recent publication we showed that the STM imaging and scanning tunneling spectroscopy of InAs(110) surfaces is strongly affected by tip-induced band bending, owing to charges which are present on localized states at the tip apex [8]. Here, we present a series of additional experimental results which demonstrate the role played by individual localized states related to atomic defects. In order to identify this role, we have imaged dopant atoms and vacancies appearing at the surface of the InAs compound semiconductor at a temperature of 4.2 K.

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Effective polarized electron emitters based on semiconductor nanostructures

Subashiev¹

2001

Phys.-Usp.

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To design high-yield products, we must consider not only the inter-chip variability but also the intra-chip variability of transistor characteristics. In this paper, we propose a statistical parameter extraction considering both intra-and inter-chip variabilities. In the proposed method, the model parameters of intra-chip variability are directly extracted from the measured current variation, so that the accuracy of current variation is expected to improve. The extracted parameters are compared with the measured delay variation of the ring oscillator to verify the accuracy of the proposed method.

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Effects of localised states and interparticle interactions on the STM/STS and AFM nanostructure diagnostics

Cited by 5 publications

References 4 publications

Scanning tunneling microscopy and spectroscopy at low temperatures of the (110) surface of Te-doped GaAs single crystals

Scanning tunneling microscopy and spectroscopy at low temperatures of the (110) surface of Te-doped GaAs single crystals

Influence of resonant tunneling on the imaging of atomic defects on InAs(110) surfaces by low-temperature scanning tunneling microscopy

Effective polarized electron emitters based on semiconductor nanostructures

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