ISLAND, TRIMER, AND CHAIN FORMATION ON THE SB-TERMINATED GAAS(111)B SURFACE

The surface structures resulting from the deposition of various covera ges of Sb on the GaAs(lll)B-(2x2) surface at room temperature, followe d by annealing in the 100-375 degrees C temperature range, have been i nvestigated using scanning tunneling microscopy. At low annealing temp eratures Sb islands are observed displaying no ordered atomic structur e, between which the As trimer based (2x2) reconstruction of the clean GaAs surface is visible. Annealing above 250 degrees C causes the for mation of Sb trimers which are distinguishable from the remaining As t rimers via contrast differences in filled- and empty-state images, Ann ealing at still higher temperatures leads to the creation of Sb chain pairs oriented along the substrate [110] directions, coexisting with r egions of Sb trimer based reconstruction between the chain pairs, The local periodicity of the patterns of Sb trimers between the chain pair s is dependent on the separation between chain pairs. (C) 1996 America n Vacuum Society.