Real time observation of reconstruction transitions on GaAs (111)B surface by scanning electron microscopy

Scanning electron microscopy (SEM) has been applied to directly observe the √19×√19 and (1×1)HT reconstructions and their transitions on the GaAs (111)B vicinal surfaces under As pressure. √19×√19 reconstruction and 1×1 high temperature reconstructions known as (1×1)HT reconstructions are observed in dark and bright contrast, respectively. During the transition, √19×√19 domains start to develop from the macrostep edges on to the lower (1×1)HT reconstructed terraces, while (1×1)HT domains start to develop from the macrostep edges on to the upper √19×√19 reconstructed terraces. The transition diagram in the surface coverage of domains shows hysteresis. Since Ga diffusion, As incorporation or reevaporation are enhanced during the transitions, heavy step bunching with rough macrostep edges is observed.