GaAs (001) - c(4x4) Rekonstruction

The c(4x4) has the highest arsenic coverage (1.75 monolayer) of all known GaAs (001) reconstructions. The c(4x4) appears in MBE at low temperatures or high arsenic pressures. In MOVPE the c(4x4) is the ruling reconstruction.

RHEED shows a 2 folded pattern every 45 degrees. A LEED image is displayed below.


LEED pattern of a c(4x4) [Veit95]

The RAS spectrum is dominated by a feature around 2.8eV (at 300K) which is assumed to be arsenic dimer related.


RAS spectrum during MBE [Hingerl93]

The arsenic coverage is 1.75 monolayers, no gallium exists on this reconstruction.

From STM pictures the following model had be constructed [Biegelsen90]:


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last changes: 6.2.1996