Observation of the superstructure at the Al–GaAs(001) interface by synchrotron x-ray diffraction

The superstructure at the Al–GaAs(001) interface has been observed for the first time by grazing incidence x-ray diffraction with the use of a synchrotron source. The Al overlayer of 150 Å in thickness was deposited on the (4×6)-reconstructed (001) GaAs surface. The Bragg peaks were observed at the fractional-order reciprocal lattice points of (n/4 l) in the [11̄0] direction and (0 m/6) in the [1̄1̄0] direction. The discussion is addressed to the correlation between interface reactions and the stability of the superstructure at the interface.