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ISSN - 19327447, Journal of Physical Chemistry C, 2013, vol. 117, p. 9723-9733

Backward reconstructions on GaAs(001) surface induced by atomic hydrogen reactions: Surfactant-assisted low-temperature surface ordering

Tereshchenko O. E., Bakulin A. V., Kulkova S. E., Eremeev S. V.

The sequence of surface reconstructions on GaAs(001), usually observed under As desorption in the temperature range from 450 to 580 C, was obtained by atomic hydrogen (AH) reaction with the oxide-covered GaAs(001) surfaces in the temperature range from 420 to 280 C. With the decrease in annealing temperature under AH treatment of oxide-covered GaAs(001) surfaces, the reconstructions changed from As-rich (2 × 4)/c(2 × 8) at 420 C through the intermediate (2 × 6)/(3 × 6) at 380 C, Ga-stabilized (4 × 2)/c(8 × 2) at 350 C and (4 × 6) at 330 C, to a very Ga-rich (4 × 4) at 280 C, in the order of Ga/As ratio increase. The observed backward reconstructions on the GaAs(001) surface are explained by AH-induced Ga accumulation on the surface and by surfactant activities of AH allowing low-temperature ordering. The Ga-rich (4 × 4) surface structure covered by ΘGa ≈ 0.8 ML was reconstructed to a new Ga-terminated structure with the symmetry of As-rich (2 × 4)/c(2 × 8) surface under vacuum annealing at the temperature higher than 560 C. DFT calculations support the existence of the energetically favored Ga-rich (2 × 4) reconstruction described by the mixed-dimer model, developed for InP(001)-(2 × 4) surface, and predict the coexistence of (2 × 4) and (4 × 4) reconstructions on GaAs(001) at the Ga-rich limit. © 2013 American Chemical Society.