Surface reconstructions of InGaAs alloys

The atomic surface structures of InGaAs lattice-matched and 1.9% compressively strained alloys were examined using in situ scanning tunneling microscopy. The surface of the lattice-matched films is comprised of an anion-rich but mixed-termination (4 × 3) or (6 × 4) reconstruction. The strained alloys exhibit regions of the same reconstructions, in addition to pockets of α2(2 × 4) in the case of the In0.27Ga0.73As/GaAs films, and β2(2 × 4) in the case of the In0.81Ga0.19As/InP. Annealing experiments show that the coverage of the α2(2 × 4) and β2(2 × 4) regions decreases with increasing annealing time. Therefore, it is postulated that the composition of these (2 × 4) reconstructions is enriched in In compared to the (4 × 3)/(6 × 4).