Photoemission-Based Photovoltage Probe of Semiconductor Surface and Interface Electronic Structure

Demuth, J. E.; Thompson, William J.; DiNardo, N. J.; Imbihl, R.

doi:10.1103/physrevlett.56.1408

Cited by 160 publications

(70 citation statements)

References 18 publications

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“…A rigid shift of 0.45 eV toward a higher binding energy, which is observed after cooling the sample to 100 K, results from the surface photovoltage effect. 23 The spectra in Fig. 2 look different from those observed previously.…”

Section: B Si 2p Core Levelcontrasting

confidence: 52%

Identification of the basic structure of the Ag/Si(111)-(6×1)surface: Observation of a low-temperaturec(12×2)phase

et al. 2001

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The surface structure of the so-called Ag/Si͑111͒-(6ϫ1) surface is studied by low-energy electron diffraction ͑LEED͒, high-resolution core-level photoelectron spectroscopy, and angle-resolved photoelectron spectroscopy. A c(12ϫ2) phase is observed in LEED after cooling the room-temperature (6ϫ1) phase to 100 K. In the Si 2p core-level spectra, no significant difference is observed between the two surfaces. In the valenceband spectra, five surface states are observed on both the (6ϫ1) and c(12ϫ2) surfaces. None of these surface states crosses the Fermi level. The binding energies and dispersions of the surface states observed on the (6 ϫ1) surface are quite similar to those of the c(12ϫ2) surface. These results indicate that the basic structure of this Ag/Si͑111͒ surface has a c(12ϫ2) periodicity, and that the (6ϫ1) structure results from thermal vibrations of the surface atoms. Moreover, we assign two of the surface states to bonding states between Ag and Si atoms, and one of them to a -bond state.

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Section: B Si 2p Core Levelcontrasting

confidence: 52%

Identification of the basic structure of the Ag/Si(111)-(6×1)surface: Observation of a low-temperaturec(12×2)phase

et al. 2001

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“…The spatial distribution of the SPV-induced charge carriers in the band-bending potential opposes the original charge distribution that gave rise to the band bending. In this way, these photoinduced charges cancel the original electrostatic potential and thus lead to a decrease in the band bending [46][47][48][49][50][51]. Insight into the delicate synergy of SPV effects and photostimulated desorption of foreign species from the sample surface will be given in Sec.…”

Section: A Bi 2 Sementioning

confidence: 99%

Dirac states with knobs on: Interplay of external parameters and the surface electronic properties of three-dimensional topological insulators

et al. 2015

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Topological insulators are a novel materials platform with high applications potential in fields ranging from spintronics to quantum computation. In the ongoing scientific effort to demonstrate controlled manipulation of their electronic structure by external means, i.e., the provision of knobs with which to tune properties, stoichiometric variation and surface decoration are two effective approaches that have been followed. In angleresolved photoelectron spectroscopy (ARPES) experiments, both approaches are seen to lead to electronic band-structure changes. Most importantly, such approaches result in variations of the energy position of bulk and surface-related features and the creation of two-dimensional electron gases. The data presented here demonstrate that a third manipulation handle is accessible by utilizing the amount of super-band-gap light a topological insulator surface has been exposed to under typical ARPES experimental conditions. Our results show that this third knob acts on an equal footing with stoichiometry and surface decoration as a modifier of the electronic band structure, and that it is in continuous and direct competition with the latter. The data clearly point towards surface photovoltage and photoinduced desorption as the physical phenomena behind modifications of the electronic band structure under exposure to high-flux photons. We show that the interplay of these phenomena can minimize and even eliminate the adsorbate-related surface band bending on typical binary, ternary, and quaternary Bi-based topological insulators. Including the influence of the sample temperature, these data set up a detailed framework for the external control of the electronic band structure in topological insulator compounds in an ARPES setting. Four external knobs are available: bulk stoichiometry, surface decoration, temperature, and photon exposure. These knobs can be used in conjunction to fine tune the band energies near the surface and consequently influence the topological properties of the relevant electronic states.

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“…12 For an n-type 100 ⍀ cm silicon crystal, the bulk Fermi level is approximately 0.75 eV above the valence-band maximum. 13 The band bending beneath the 7ϫ7 surface is thus only about 0.1 eV, and so the space charge layer region has a conductance close to that of the bulk.…”

Section: ͓S0003-6951͑00͒02749-2͔mentioning

confidence: 99%

Microfour-point probe for studying electronic transport through surface states

Petersen

Grey

Shiraki

et al. 2000

Applied Physics Letters

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Microfour-point probes integrated on silicon chips have been fabricated with probe spacings in the range 4–60 μm. They provide a simple robust device for electrical transport measurements at surfaces, bridging the gap between conventional macroscopic four-point probes and scanning tunneling microscopy. Measurements on Si(111) surfaces in ultrahigh vacuum reveal that the Si(111)–√3×√3–Ag structure induced by a monolayer of Ag atoms has a four-point resistance two orders of magnitude lower than that of the Si(111)–7×7 clean surface. We attribute this remarkable difference to direct transport through surface states, which is not observed on the macroscopic scale, presumably due to scattering at atomic steps.

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Photoemission-Based Photovoltage Probe of Semiconductor Surface and Interface Electronic Structure

Cited by 160 publications

References 18 publications

Identification of the basic structure of the Ag/Si(111)-(6×1)surface: Observation of a low-temperaturec(12×2)phase

Identification of the basic structure of the Ag/Si(111)-(6×1)surface: Observation of a low-temperaturec(12×2)phase

Dirac states with knobs on: Interplay of external parameters and the surface electronic properties of three-dimensional topological insulators

Microfour-point probe for studying electronic transport through surface states

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