Scanning tunnelling microscopy was used to study the transition in surface structure between the As-terminated 2 x 4 and c(4 x 4) reconstructions as a function of the surface temperature under an As2 flux. In both materials, 2-phase surface reconstructions existed throughout the transition regime. In the case of GaAs, the 2-phase surface consisted of disordered (2 x 4)-like structures plus a c(4 x 4)-like phase which terminated 1 monolayer below the 2 x 4 surface. In the case of InAs, a disordered asymmetrical 1 x 3 phase occurred in addition to the main phases; 1 monolayer below each main phase. In both cases, simple addition of As via As-on-As chemisorption could not account for the formation of the c(4 x 4) reconstruction from the 2 x 4 surface. The c(4 x 4) phase was inherently multi-layered. This explained how the structure could form without the addition or removal of the group-III component and still maintain its layering registry with the residual 2 x 4 or a(1 x 3) phase. A result of this formation process was the necessary intermixing of group-III and group-V species in the second layer of the c(4 x 4) reconstruction.

Species intermixing and phase transitions on the reconstructed (001) surfaces of GaAs and InAs G.R.Bell, J.G.Belk, C.F.McConville, T.S.Jones: Physical Review B, 1999, 59[4], 2947-55