Si‐doped (211)A and (311)A GaAs samples grown by molecular beam epitaxy (MBE) with various growth As pressures have been studied. Hall effect measurements have revealed that the doping changes fromptontype by increasing the As pressure. The transition As pressure is lower for the (211)A than for the (311)A surfaces. Photoluminescence measurements have shown that by increasing the As pressure, arsenic vacancy defects are changed into pairs of Ga vacancy and Ga antisite defects. These results are explained by considering the orientation dependence of the surface bonding and the kinetics of the MBE growth process. ©1995 American Institute of Physics.