A prospective: Quantitative scanning tunneling spectroscopy of semiconductor surfaces

Feenstra, R. M.

doi:10.1016/j.susc.2009.08.002

Cited by 23 publications

(19 citation statements)

References 27 publications

(39 reference statements)

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“…Fig. [33][34][35][36][37] When the surface is photoilluminated, the redistribution of photocarriers reduces the electric eld and changes the surface potential (surface photovoltage: SPV), and thus increases the effective bias voltage applied to the tunnel junction ( Fig. Under a reverse bias voltage condition, i.e., a positive bias voltage is applied to an n-type semiconductor, the so-called tip-induced band bending (TIBB) occurs owing to the leakage of the electric eld applied between the STM tip and the sample ( Fig.…”

Section: Introductionmentioning

confidence: 99%

Bases for time-resolved probing of transient carrier dynamics by optical pump–probe scanning tunneling microscopy

et al. 2013

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The tangled mechanism that produces optical pump-probe scanning tunneling microscopy spectra from semiconductors was analyzed by comparing model simulation data with experimental data. The nonlinearities reflected in the spectra, namely, the excitations generated by paired laser pulses with a delay time, the logarithmic relationship between carrier density and surface photovoltage (SPV), and the effect of the change in tunneling barrier height depending on SPV, were examined along with the delay-time-dependent integration process used in measurement. The optimum conditions required to realize reliable measurement, as well as the validity of the microscopy technique, were demonstrated for the first time.

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Section: Introductionmentioning

confidence: 99%

Bases for time-resolved probing of transient carrier dynamics by optical pump–probe scanning tunneling microscopy

et al. 2013

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“…These algorithms, recently summarized by Passoni et al 11 have led to a better understanding of the STS experiment but they have not yet been widely adopted in the experimental studies. 13 The reason for this is the considerable computational effort required coupled with the need for very accurate data and the fact that a knowledge of two nondirectly measurable quantities ͑tunneling barrier height and absolute tip-surface separa-tion͒ are required for LDOS recovery. Thus to benefit from the full potential of the recovery scheme efforts should be made to acquire good quality data over the entire energy range and to develop a simple and fast data processing procedures for parameter determination.…”

Section: Introductionmentioning

confidence: 99%

Variable-height scanning tunneling spectroscopy for local density of states recovery based on the one-dimensional WKB approximation

Naydenov

Boland

2010

Phys. Rev. B

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We introduce a variable-height scanning tunneling spectroscopy ͑VH-STS͒ method that provides a good level of recovery of the combined surface and tip density of states ͑DOS͒ in any bias range without the complexity of previous methods. The combined local electron DOS ͑LDOS͒ recovery was performed using a simplified algorithm based on the one-dimensional Wentzel-Kramers-Brillouin approximation already known in the literature. On the basis of this VH-STS approach we derive three separate methods for the determination of tunnel barrier height and absolute tip-surface separation, and which are critical to enabling LDOS recovery. We report experimental results on polycrystalline-Pt and Si͑100͒ surfaces using this scheme. Experimental and simulated spectra are compared to investigate the limits of the various methods and to demonstrate that this approach can be applied successfully to all kind of probes and surfaces.

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“…This effect is called tip-induced band bending. 96 Some of the applied voltage between the tip and sample is dropped within the semiconductor, leading to an additional band bending and the formation/modification of the space charge layer. A simple one-dimensional model of the tip-induced band bending is outlined in the supplementary material, using the Schottky approximation for the space charge layer.…”

Section: Influence Of the Presence Of The Probing Tipsmentioning

confidence: 99%

“…For quantitative results, a more realistic three-dimensional treatment has to be performed. 96 A sketch how a modified band bending might look like for the case of a nanowire is shown in Fig. 22(c).…”

Section: Influence Of the Presence Of The Probing Tipsmentioning

confidence: 99%

Invited Review Article: Multi-tip scanning tunneling microscopy: Experimental techniques and data analysis

Voigtländer

Cherepanov

Korte

et al. 2018

Review of Scientific Instruments

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In scanning tunneling microscopy, we witness in recent years a paradigm shift from "just imaging" to detailed spectroscopic measurements at the nanoscale and multi-tip scanning tunneling microscope (STM) is a technique following this trend. It is capable of performing nanoscale charge transport measurements like a "multimeter at the nanoscale." Distance-dependent four-point measurements, the acquisition of nanoscale potential maps at current carrying nanostructures and surfaces, as well as the acquisition of I − V curves of nanoelectronic devices are examples of the capabilities of the multi-tip STM technique. In this review, we focus on two aspects: How to perform the multi-tip STM measurements and how to analyze the acquired data in order to gain insight into nanoscale charge transport processes for a variety of samples. We further discuss specifics of the electronics for multi-tip STM and the properties of tips for multi-tip STM, and present methods for a tip approach to nanostructures on insulating substrates. We introduce methods on how to extract the conductivity/resistivity for mixed 2D/3D systems from four-point measurements, how to measure the conductivity of 2D sheets, and how to introduce scanning tunneling potentiometry measurements with a multi-tip setup. For the example of multi-tip measurements at freestanding vapor liquid solid grown nanowires, we discuss contact resistances as well as the influence of the presence of the probing tips on the four point measurements.

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A prospective: Quantitative scanning tunneling spectroscopy of semiconductor surfaces

Cited by 23 publications

References 27 publications

Bases for time-resolved probing of transient carrier dynamics by optical pump–probe scanning tunneling microscopy

Bases for time-resolved probing of transient carrier dynamics by optical pump–probe scanning tunneling microscopy

Variable-height scanning tunneling spectroscopy for local density of states recovery based on the one-dimensional WKB approximation

Invited Review Article: Multi-tip scanning tunneling microscopy: Experimental techniques and data analysis

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