Hydrogen induced derelaxation on a MBE grown GaAs(110) surface

Ruocco, Alessandro; Nannarone, Stefano; Sauvage‐Simkin, M.; Jedrecy, N.; Pinchaux, R.; Waldhauer, A.

doi:10.1016/0039-6028(94)91473-7

Cited by 28 publications

(7 citation statements)

References 19 publications

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“…When an adsorbed atom bonds to one of the buckled dimmer, it operates to release the buckling, as hydrogen adsorption on the GaAs(110) surface lifts the buckling of the surface Ga-As dimer. This effect of H adsorption is supported experimentally [20][21][22][23][24][25][26] and theoretically. [27][28][29][30][31][32] Adsorption on the InAs(110) surface leads to donor-type surface states above but near the CBM.…”

Section: Introductionsupporting

confidence: 53%

Accurate evaluation of subband structure in a carrier accumulation layer at an n-type InAs surface: LDF calculation combined with high-resolution photoelectron spectroscopy

2012

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Adsorption on an n-type InAs surface often induces a gradual formation of a carrieraccumulation layer at the surface. By means of high-resolution photoelectron spectroscopy (PES), Betti et al. made a systematic observation of subbands in the accumulation layer in the formation process. Incorporating a highly nonparabolic (NP) dispersion of the conduction band into the local-density-functional (LDF) formalism, we examine the subband structure in the accumulation-layer formation process. Combining the LDF calculation with the PES experiment, we make an accurate evaluation of the accumulated-carrier density, the subband-edge energies, and the subband energy dispersion at each formation stage. Our theoretical calculation can reproduce the three observed subbands quantitatively. The subband dispersion, which deviates downward from that of the projected bulk conduction band with an increase in wave number, becomes significantly weaker in the formation process.

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Section: Introductionsupporting

confidence: 53%

Accurate evaluation of subband structure in a carrier accumulation layer at an n-type InAs surface: LDF calculation combined with high-resolution photoelectron spectroscopy

2012

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“…As the dissociation rate strongly depends on the size and temperature of the filament, as well as on the distance to the surface, it is difficult to relate the molecular exposure given here with fractions of ML or with experiments done at other laboratories. For this reason, following previous works [8][9][10][11][12][13][14][15] the exposures are given in Langmuirs of H 2 ͑1Lϭ10 Ϫ6 Torr sec͒.…”

Section: Experimental Methodsmentioning

confidence: 99%

“…From the attenuation of the LEED spots and the photoemission yields measured as a function of the H exposure, M'Hamedi et al 13 concluded that the adsorbed H atoms derelax the surface ͑in this work, no quantitative determination of the surface atomic position was performed͒. More recently, using grazing incidence x-ray diffraction 14 ͑GIXD͒ and photoelectron diffraction ͑PD͒, 15 Ruocco et al, assuming H coverages of 1 and 1/4 ML, have proposed values for of Ϫ5°and 6°, respectively.…”

Section: Introductionmentioning

confidence: 95%

“…Since the hydrogen layer produces a small effect on keV heavy-ion trajectories, TOF-ISS should be able to detect the changes in the surface atomic structure with an accuracy similar to that of the clean surface. A difference between TOF-ISS and the diffraction techniques used to study this surface [13][14][15] is that it samples directly ͑in real space͒ the ion core positions and that along certain crystallographic directions it is relatively easy to separate the contributions of the top layer from those of deeper layers. To our knowledge this is the first time that ion-scattering spectrometry is applied to the study of the H:GaAs͑110͒ surface.…”

Section: Introductionmentioning

confidence: 99%

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Atomic-structure characterization of a H:GaAs(110) surface by time-of-flight ion-scattering spectrometry

et al. 1997

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We have used ion-scattering spectrometry with time-of-flight analysis ͑TOF͒ to study the atomic structure of a GaAs͑110͒ surface exposed to atomic hydrogen. The TOF spectra of ions plus neutrals acquired for 6 keV Ne ϩ backscattering from both As and Ga top-layer atoms show a strong dependence on the projectile incidence direction and on the hydrogen exposure. The variations in the quasisingle backscattered intensity derived from the TOF spectra were analyzed with a code that calculates shadowing and focusing regions in a two-atom model. Measurements as a function of the hydrogen exposure indicate that the surface derelaxes approaching the ideal bulk termination. At the beginning of the adsorption the fraction of the surface that undergoes derelaxation increases very fast with exposure. At higher exposures, the rate of derelaxation becomes slower and the TOF spectra tend to a steady state. From Ne quasisingle backscattered intensities, measured as a function of the incident angle, we have determined that the spacing between the top As and Ga layers is reduced from (⌬Zϭ0.66Ϯ0.08) Å for the clean surface to (⌬Zϭ0.0Ϯ0.08) Å for intermediate exposures ͑2000 L H 2 ). At this exposure we have found a spacing between the first and second layers of (1.8Ϯ0.1) Å. At higher exposures the results indicate a small counter-relaxation.

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“…However, when a hydrogen ͑H͒ atom bonds to one of the relaxed dimer, it operates to remove the relaxation of the dimer, which results in the appearance of a midgap surface state from the other atom of the dimer. The fact that H adsorption removes the surface relaxation is supported both experimentally [12][13][14][15][16][17][18] and theoretically. [19][20][21][22][23][24] The theoretical calculation for the case of submonolayer H coverages in Refs.…”

Section: Introductionmentioning

confidence: 56%

Evolution of elementary excitations at a doped polar semiconductor surface in a depletion-layer formation process

Inaoka

2001

Phys. Rev. B

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We investigate the evolution of elementary excitations at a doped polar semiconductor surface in a depletion-layer formation process. The elementary excitations analyzed are two coupled plasmon-phonon modes and a surface optical-phonon mode involving screening charges. Surface excitations of free carriers are calculated by taking account of the Coulomb interaction between carriers, the dynamical exchange-correlation effect, and the coupling with surface polar phonons, on the basis of thermal-equilibrium states calculated self-consistently by the local-density approximation. We focus our attention on the coupling character and the spatial structure of each surface-excitation mode, as well as the energy dispersion and the energy-loss intensity involved in the excitation. The induced charge-density distribution in the excitation mode is composed of a carrier component due to carrier density fluctuation, a phonon component arising from longitudinal polarphonon polarization, and two on-surface components originating from the termination of the polar phonon and background polarization at the surface. The coupling character is elucidated by the phase relation and the amplitude ratio among these induced charge components. The spatial structure is visualized by the contour map of the induced charge-density distribution. We follow the variation in the coupling character and the spatial structure in the depletion-layer formation process. Our analysis gives a clear explanation of the variation in each of the three loss peaks in the electron energy-loss spectrum.

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Hydrogen induced derelaxation on a MBE grown GaAs(110) surface

Cited by 28 publications

References 19 publications

Accurate evaluation of subband structure in a carrier accumulation layer at an n-type InAs surface: LDF calculation combined with high-resolution photoelectron spectroscopy

Accurate evaluation of subband structure in a carrier accumulation layer at an n-type InAs surface: LDF calculation combined with high-resolution photoelectron spectroscopy

Atomic-structure characterization of a H:GaAs(110) surface by time-of-flight ion-scattering spectrometry

Evolution of elementary excitations at a doped polar semiconductor surface in a depletion-layer formation process

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