Sb incorporation at GaAs(0 0 1)-(2 × 4) surfaces

We examine the Sb incorporation and resulting surface reconstructions of Sb and GaSb deposited on GaAs(0 0 1). These films exhibit a mixed surface reconstruction of α2(2 × 4) and α(4 × 3). Initially, Sb reacts with Ga on the surface to form 2D islands of GaSb with an α(4 × 3) surface reconstruction. The 2D islands grow to a critical size of 30 nm², beyond which the atomic surface structure of the 2D island transforms to a α2(2 × 4) reconstruction in order to reduce the strain induced surface energy. This transformation is limited by the availability of Ga, which is necessary in higher quantities for the α2(2 × 4) reconstruction than for the α(4 × 3). The transformation results in a mixed α2(2 × 4)-α(4 × 3) surface where the surface reconstruction is coupled to the surface morphology, which may in the future provide a pathway for self-assembly of structures.