As and Ga dimers in core-level spectroscopy of S-passivated GaAs(001)

Abstract

Photoluminescence and xray photoelectron spectroscopy study of Spassivated InGaAs (001) We performed a correlated study of sulfide-passivated GaAs͑001͒ surfaces, using x-ray photoelectron spectroscopy and reflection anisotropy spectroscopy. The reflection anisotropy spectra reveal after desorption of the sulfide overlayer the presence of As and Ga dimers analogous to ones observed on As-decapped surfaces. We identify in the 3d core-level spectra the surface components due to As and Ga dimers: their chemical shifts are Ϫ0.28 and Ϫ0.35 eV, respectively. We propose an interpretation of the main surface components in the framework of a simple model, based on charge neutrality, electron counting, and electronegativity concepts.

Surface Chemistry of Prototypical Bulk II−VI and III−V Semiconductors and Implications for Chemical Sensing

“…In addition to the aforementioned techniques, reflectance anisotropy spectroscopy (RAS) has recently been developed to probe the presence of oriented surface dimer species on polar semiconductors. − This technique relies on the low symmetry of the surfaces of cubic semiconductors and is based on measuring the difference in reflectivity of polarized light along two orthogonal axes of the surface. The bulk contribution disappears in this analysis, making the measurement sensitive to the presence of surface adsorbates aligned with the two axes, even when the adsorbates are covered by an amorphous overlayer.…”

“…However, the interpretation of the RAS spectral signal is often difficult. The technique has been used successfully to observe the appearance and removal of surface dimers of Ga or As on GaAs surfaces. , …”

“…The technique has been used successfully to observe the appearance and removal of surface dimers of Ga or As on GaAs surfaces. 44,45 Temperature-programmed desorption (TPD) provides a surface compositional analysis based on mass spectrometry of desorbed adsorbates. The sensitivity of mass spectrometric detection allows analysis of coverages less than 0.1% of a monolayer.…”

Model experiments on growth modes and interface electronics of CuInS2 : Ultrathin epitaxial films on GaAs(100) substrates

“…This is also supported by a relatively large value of 2.3 eV of the line width for both components, namely (I) and (III). The As 3d peak consists of two peak structures labeled (I) and (II), which are assigned to surface and bulk related contributions . After the heating treatment, the total intensity of the As 3d peak remains more or less unchanged with a diminished surface component (I) and an elevated bulk component (II).…”