Abstract:
This paper presents experimental results of an ultrahigh vacuum
study of
4${\times}$2/c(8${\times}$2)${\longrightarrow}$2${\times}$4/c(2${\times}$8)
structural transition on GaAs(001) caused by the thermal removal of the
saturated iodine monolayer formed at
GaAs(001)-4${\times}$2/c(8${\times}$2).
It has been found out that the original
c(8${\times}$2) low energy electron
diffraction pattern transforms into 4${\times}$1 at
0.6 ML of iodine coverage
and then keeps up to its saturation at 1.0 ML.
We have determined that GaI is
the only chemical product of the iodine action, its double peak was observed
in the thermal desorption spectra at $T = 150{\div}370\,^{\circ}$C. The
explanation of surface processes underlying
4${\times}$2/c(8${\times}$2)${\longrightarrow}$2${\times}$4/c(2${\times}$8)
phase transition is presented below.
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