Abstract :
The site occupancy of Si introduced as a dopant in the growth of GaAs on GaAs(111)A has been shown to be very sensitive to growth conditions. We have examined the effect of modulating the As4 and Ga fluxes on this behaviour. Supplying Ga and As sequentially rather than simultaneously always results in a much stronger tendency for the Si to occupy an As site and act as an acceptor than for material grown by conventional molecular beam epitaxy. The same result is obtained irrespective of whether the Si is supplied with the As or Ga.
