Diffusion of Si-acceptor in δ-doped GaAs grown on GaAs(111)A by molecular beam epitaxy

Diffusion of Si-acceptors (Si occupying As sites) in δ-doped GaAs grown on GaAs(111)A has been investigated by secondary ion mass spectrometry (SIMS). We have measured the diffusion parameters in GaAs(111)A and found that they differ from those in GaAs(001). The diffusion coefficient in GaAs(111)A is smaller than that in GaAs(001) and the activation energy in GaAs(111)A is larger than that in GaAs(001). Furthermore, the diffusion mechanism of Si in GaAs(111)A has been investigated by photoluminescence; we have found that in p-type layers Si-donors (Si occupying Ga sites) diffuse easily to As sites. The activation energy of Si-acceptor diffusion is 2.74±0.11 eV. These results indicate that Si-acceptors are more stable than Si-donors.