By using an electrostatic force microscope, measurements were made of surface contact potential variations across antiphase boundaries on films which had been grown onto Ge substrates. The surface contact potential at the antiphase boundaries was consistently measured to be 30mV higher than that at GaAs domains. This was attributed to the Fermi levels being pinned at different surface states. The fact that an identical electrical behavior was observed for all of the antiphase boundaries indicated that they were the lowest-energy {110} orientation. The sign of the observed Fermi-level shift was consistent with a predominance of Ga-Ga bonds at real {110} antiphase boundaries.

Direct measurement of surface defect level distribution associated with GaAs antiphase boundaries Q.Xu, J.W.P.Hsu: Physical Review Letters, 1999, 82[3], 612-5