Stoichiometry Study of S-Terminated GaAs(001)-(2 ×6) Surface with Synchrotron Radiation Photoelectron Spectroscopy

Abstract

Synchrotron radiation photoelectron spectroscopy (SRPES) has been performed to investigate the surface stoichiometry of the S-terminated GaAs(001)-(2 × 6), and in particular, to determine the chemical species of the five dimers, which are separated by missing dimers and form the unit structure of the (2 × 6) reconstruction. The S 2p photoemission spectra show a significant decrease in the peak intensity with increasing substrate temperature, whereas no significant changes are observed for the As 3d photoemission spectra The Ga 3d spectra are decomposed into a bulk component and more than one surface component, one of which is attributed to a Ga-S bond and decreases in accordance with the change observed in the S 2p spectra. These results strongly support the model that each pair of the five dimers in the (2 × 6) reconstruction consists of S-S dimers.

New value of old knowledge: sulphur-based GaAs surface passivation and potential GaAs application in molecular electronics and spintronics

“…Figure 10 shows that a near-stoichiometric GaAs surface with (4 × 1) surface reconstruction was observed with a completely unpinned surface Fermi level after the same S passivation followed by annealing treatment [85]. Another surface reconstruction (2×6), which is also considered to be stable, was reported to have five S dimers in a unit [116,117]. On heating, this dimmer row breaks out from the middle to yield a (2 × 3) surface recombination.…”