Ga-rich GaP(001)(2×4) surface structure studied by low-energy ion scattering spectroscopy

Naitoh, Masamichi; Konishi, Akira; Inenaga, H; Nishigaki, S.; Oishi, Nobuhiro; Shoji, Fumiya

doi:10.1016/s0039-6028(97)00902-3

Cited by 11 publications

(8 citation statements)

References 13 publications

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“…[38][39][40] The BE of the Ga 2p 3/2 peak maximum for the Ga-P bonds is located at 1117.3 eV, while a small shoulder at BE of 1116.8 eV is expected to appear in the event of a metallic phase formation (Ga-Ga bonds). High-purity silver paint (from Supplies SPI, USA) was used to increase conductivity, and the sample was thoroughly degassed before it was introduced into the system.…”

Section: Introductionmentioning

confidence: 99%

Distinct and dramatic water dissociation on GaP(111) tracked by near-ambient pressure X-ray photoelectron spectroscopy

Zhang

Ptasińska

2015

Phys. Chem. Chem. Phys.

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Water adsorption and dissociation on a GaP(111) crystal surface are investigated using near-ambient pressure X-ray photoelectron spectroscopy (NAP XPS) in a wide range of pressures (∼10(-10)-5 mbar) and temperatures (∼300-773 K). Dynamic changes in chemical evolution at the H2O/GaP(111) interface are reflected in Ga 2p3/2, O 1s, and P 2p spectra. In the pressure-dependent study performed at room temperature, an enhancement of surface Ga hydroxylation and oxidation with an increase in H2O pressure is observed. In the temperature-dependent study performed at elevated pressures, two distinct regions can be defined in which drastic changes occur in the surface chemistry. Below 673 K, the surface Ga hydroxylation and oxidation progress continuously. However, above 673 K, a large-scale conversion of surface O-Ga-OH species into non-stoichiometric Ga hydroxide along with oxidation of surface P atoms occurs through an intermediate state. The NAP XPS technique enabled us to experimentally track the chemistry at the H2O/GaP interface under near-realistic conditions, thereby providing evidence to compare with recent theoretical efforts to improve the understanding of water-splitting mechanisms and photo-corrosion on semiconductor surfaces.

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Section: Introductionmentioning

confidence: 99%

Distinct and dramatic water dissociation on GaP(111) tracked by near-ambient pressure X-ray photoelectron spectroscopy

Zhang

Ptasińska

2015

Phys. Chem. Chem. Phys.

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“…4, on the other hand, clear differences between the scanning tunneling microscopy ͑STM͒ images recorded on sputtered/annealed GaP͑001͒ surfaces and the corresponding data for GaAs͑001͒(4ϫ2)/c(8ϫ2) surfaces 11 are reported. In a more recent publication by the same group, 12 examining the atomic structure by ion scattering, the symmetry was corrected to a (2ϫ4). (2ϫ4) reconstructions under Ga as well as under P supply were also observed in MBE experiments of Ref.…”

Section: Introductionmentioning

confidence: 99%

(2×4)GaP(001) surface: Atomic structure and optical anisotropy

et al. 1999

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We have investigated the microscopic structure and optical anisotropy of (2ϫ4) reconstructed GaP͑001͒ surfaces. Optical and electron spectroscopy from GaP͑001͒ surfaces prepared in ultrahigh-vacuum conditions were combined with first-principles calculations of the energetics and reflectance anisotropy. Symmetry, composition and surface optical anisotropy were characterized by low-energy electron diffraction, Auger electron spectroscopy, photoemission spectroscopy and reflectance anisotropy spectroscopy. In contrast to most earlier reports, we find that the stable Ga-rich surface corresponds to a (2ϫ4) reconstruction. No (4ϫ2) reconstruction could be observed, independent of the preparation method. Depending on the Ga coverage, however, two distinct line shapes in the reflection anisotropy spectra occur, indicating the existence of at least two different surface phases with (2ϫ4) periodicity. This agrees with our total-energy calculations: Four (2ϫ4) structural models may be stable depending on the chemical potentials of the surface constituents. All considered (4 ϫ2) structures, however, are unstable. Based on the comparison between calculated reflectance anisotropy spectra and measured data we suggest mixed GaP dimers on top of the Ga-terminated substrate as groundstate geometry for the cation-rich phase of GaP͑001͒(2ϫ4). Our results indicate the formation of P dimers at the surface for the more anion-rich phase of GaP͑001͒(2ϫ4). ͓S0163-1829͑99͒02828-3͔

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“…Available experimental studies lead to different and partially contradictive conclusions about the symmetry and structure of the GaP͑001͒ surface. 9 In a more recent investigation by ion scattering, 22 9 In a more recent investigation by ion scattering, 22 …”

Section: Introductionmentioning

confidence: 99%

GaP(001) and InP(001): Reflectance anisotropy and surface geometry

Esser

Schmidt

Bernholc

et al. 1999

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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We have investigated the optical anisotropy of GaP͑001͒ and InP͑001͒ surfaces. The samples were prepared by homoepitaxial metalorganic vapor phase epitaxy growth and either directly transferred into ultrahigh vacuum ͑UHV͒ or in situ capped and, after transfer, decapped in UHV by thermal desorption of a P/As capping layer. Symmetry, composition, and surface optical anisotropy were characterized by low-energy electron diffraction, Auger electron spectroscopy, and reflectance anisotropy spectroscopy. We observe (2ϫ1)/(2ϫ2)-like reconstructions for the very P-rich and (2ϫ4) reconstructions for the more cation-rich surfaces. No (4ϫ2) reconstruction could be prepared, independent of the preparation method. A comparison of the reflectance anisotropy between GaP͑001͒ and InP͑001͒ surfaces shows similar line shapes for the very cation-rich (2ϫ4) surfaces. For less cation-rich surfaces, however, we observe distinct differences between the spectra of the two systems. In both cases, different line shapes in the reflection anisotropy spectra occur for the (2ϫ4) periodicity, suggesting the existence of different (2ϫ4) geometries. The experimental results are discussed on the background of atomic structures, total energies and reflectance anisotropy spectra obtained ab initio from density-functional theory local-density approximation calculations.

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Ga-rich GaP(001)(2×4) surface structure studied by low-energy ion scattering spectroscopy

Cited by 11 publications

References 13 publications

Distinct and dramatic water dissociation on GaP(111) tracked by near-ambient pressure X-ray photoelectron spectroscopy

Distinct and dramatic water dissociation on GaP(111) tracked by near-ambient pressure X-ray photoelectron spectroscopy

(2×4)GaP(001) surface: Atomic structure and optical anisotropy

GaP(001) and InP(001): Reflectance anisotropy and surface geometry

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