The structure, stoichiometry and electronic properties of the GaAs(001)-(2 x 4)/c(2 x 8) surface treated by cycles of atomic hydrogen exposure and subsequent annealing in ultra-high vacuum were studied with the aim of preparing the Ga-rich surface at low temperatures. Low energy electron diffraction showed reproducible structural transformations in each cycle: atomic hydrogen adsorption at the (2 x 4)/c(2 x 8) surface led to the (1 x 4) structure at low atomic hydrogen exposure and to a (1 x 1) surface at higher atomic hydrogen exposure with subsequent restoration of the (2 x 4)/c(2 x 8) structure under annealing at 450C. The cycles of atomic hydrogen treatment preserved the atomic flatness of the GaAs(100) surface, keeping the mean roughness on to about 0.15nm. The atomic hydrogen treatment cycles led to the oscillatory behaviour of 3dAs/3dGa ratio with a gradual decrease to the value characteristic for the Ga-rich surface. Similar oscillatory variations were observed in the work function. The results were consistent with the loss of As from the surface as a result of the desorption of volatile compounds which were formed after reaction with H. The prepared Ga-rich GaAs(001) surface showed the stability of the (2 x 4)/c(2 x 8) structure up to the annealing temperature of 580C.

New Reconstruction-Stoichiometry Correlation for GaAs(001) Surface Treated by Atomic Hydrogen. K.V.Toropetsky, O.E.Tereshchenko, D.A.Petukhov, A.S.Terekhov: Applied Surface Science, 2008, 254[24], 8041-5