Change in the electronic properties of an InAs (111)A surface at oxygen and fluorine adsorption

Eremeev, S. V.; Valisheva, N. A.; Tereshchenko, O. E.; Kulkova, S. E.

doi:10.1134/s1063782612010083

Cited by 8 publications

(19 citation statements)

References 14 publications

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“…As was mentioned above, oxygen adsorption leads to the appearance of additional surface states in the semiconductor band gap with the structure strongly depending on the adsorbate geometry (Figure a–c), which indicates the local character of the adsorbate–surface interaction. It is demonstrated in Figure d,e that fluorine coadsorption on the InAs(111)-(1 × 1) unreconstructed surface decreases the density of surface states in the band gap, just as on the reconstructed InAs(111)-(2 × 2) surface, though it does not remove them completely. In general, fluorine slightly shifts oxygen-induced surface states toward the conduction band.…”

Section: Resultsmentioning

confidence: 97%

“…In the present work, in order to understand the FAOL/InAs interface formation mechanism, we study the influence of oxygen and fluorine coadsorption and also fluorine concentration on the electron properties of the InAs(111)-(1 × 1) unreconstructed surface. The grounding for such calculations is the investigations of FAOL/InAs(111)A interface morphology carried out earlier by high-resolution electron microscopy (HREM), which showed the formation of a well-ordered (crystalline) interface and a transition region of four to six atomic layers thickness. , As follows from these experimental results, the structure of the semiconductor at the interface is rather ideal compared to the reconstructed one that was considered in our previous work . Oxygen and fluorine adsorption and their coadsorption are also studied on the GaAs(111)-(1 × 1) surface to reveal the influence of semiconductor (cation) composition on the change of the surface electronic structure.…”

Section: Introductionmentioning

confidence: 87%

“…Both adsorbates are considered in the top (T) sites above surface cation and subsurface anion and also in the bridge site between cations. We note that more sites were considered in the case of the reconstructed surface in our previous work due to its more complex structure …”

Section: Computational Detailsmentioning

confidence: 99%

“…At present, ab initio calculations within methods based on the density functional theory, which allow a detailed investigation of the electron states and chemical bonds at interfaces, are actively used to understand interface states appearance/disappearance mechanisms . Earlier we studied fluorine and oxygen adsorption and their coadsorption on the InAs(111)-(2 × 2) reconstructed surface, which has an indium vacancy in the surface layer . The influence of electronegative adsorbates, including their coadsorption, on the electron properties of the InAs(111)-(1 × 1) unreconstructed surface has not been analyzed in detail.…”

Section: Introductionmentioning

confidence: 99%

“…3,4 As follows from these experimental results, the structure of the semiconductor at the interface is rather ideal compared to the reconstructed one that was considered in our previous work. 9 Oxygen and fluorine adsorption and their coadsorption are also studied on the GaAs(111)-(1 × 1) surface to reveal the influence of semiconductor (cation) composition on the change of the surface electronic structure.…”

Section: ■ Introductionmentioning

confidence: 99%

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Fluorine and Oxygen Adsorption and Their Coadsorption on the (111) Surface of InAs and GaAs

et al. 2016

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Oxygen and fluorine adsorption and their coadsorption on the (111) unreconstructed surface of semiconductors InAs and GaAs were studied using the projector augmented-wave method with the generalized gradient approximation for the exchange−correlation functional and hybrid functional approach. The energetically preferable adsorbate sites on the surface were determined. It is shown that fluorine adsorption above surface cations on the A III B V (111)A-(1 × 1) unreconstructed surface leads to a removal of the surface state formed by cation p z -orbitals and to an unpinning of the Fermi level, whereas oxygen adsorption induces additional surface states in the band gap. The influence of fluorine and oxygen coadsorption and also fluorine concentration on the surface states in the band gap is discussed. It is shown that oxygen-induced surface states are completely or partially removed from the band gap by fluorine coadsorption if it forms bonds with cation surface atoms involved in an interaction with oxygen. The increase of fluorine concentration leads to considerable changes of the near-surface-layer structure due to the penetration of both electronegative adsorbates into the substrate and affects the electron properties of oxygen/ A III B V (111) interface.

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Section: Resultsmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 87%

Section: Computational Detailsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

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Fluorine and Oxygen Adsorption and Their Coadsorption on the (111) Surface of InAs and GaAs

et al. 2016

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Oxide-free InAs(111)A interface in metal-oxide-semiconductor structure with very low density of states prepared by anodic oxidation

Valisheva

Aksenov

Golyashov

et al. 2014

Applied Physics Letters

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In this letter, we present structural, compositional, and electrical characteristics of anodic oxide layer-based metal-oxide-semiconductor (MOS) capacitors on n-type InAs(111)A, along with the effect of a thin fluorinated interfacial passivation layer. Electrochemical oxidation in acid electrolyte with addition of fluorine (NH4F) led to the formation of oxygen free well-ordered wide gap fluorinated interfacial layer at InAs(111)A with the fixed charge (Qfix) and density of interface states (Dit) in the range of (4–6) × 1010 cm−2 and (2–12) × 1010 eV−1 cm−2, respectively. We found that MOS capacitors showed excellent capacitance-voltage characteristics with very small frequency dispersion (<1% and <15 mV). Fluorinated interfacial layer consists of crystalline isostructural compound with the InAs substrate, which remains intact with the atomic smoothness and sharpness that explain unpinned behavior of the Fermi level.

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InAs-based metal-oxide-semiconductor structure formation in low-energy Townsend discharge

Aksenov

Kokhanovskii

Polovodov

et al. 2015

Applied Physics Letters

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We developed and applied a method of InAs passivation in the low-energy plasma of Townsend discharge. The controlled interface oxidation in the Ar:O2:CF4 gas mixture under visualization of gas discharge plasma allowed growing thin homogeneous films in the range of 5–15 nm thickness. Oxidation with the addition of CF4 in gas-discharge plasma led to the formation of In and As oxyfluorides with a wide insulating gap and isostructural interface with unpinned Fermi level behavior. The metal-oxide-semiconductor structure showed excellent capacitance-voltage characteristics: small frequency dispersion (<15 mV), density of interface states (Dit) in the gap below 5 × 1010 eV–1cm−2, and fixed charge (Qfix) below 5 × 1011 cm−2.

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Change in the electronic properties of an InAs (111)A surface at oxygen and fluorine adsorption

Cited by 8 publications

References 14 publications

Fluorine and Oxygen Adsorption and Their Coadsorption on the (111) Surface of InAs and GaAs

Fluorine and Oxygen Adsorption and Their Coadsorption on the (111) Surface of InAs and GaAs

Oxide-free InAs(111)A interface in metal-oxide-semiconductor structure with very low density of states prepared by anodic oxidation

InAs-based metal-oxide-semiconductor structure formation in low-energy Townsend discharge

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