Backward Reconstructions on GaAs(001) Surface Induced by Atomic Hydrogen Reactions: Surfactant-Assisted Low-Temperature Surface Ordering

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• 作者：O. E. Tereshchenko ; A. V. Bakulin ; S. E. Kulkova ; S. V. Eremeev
• 刊名：The Journal of Physical Chemistry C
• 出版年：2013
• 出版时间：May 16, 2013
• 年：2013
• 卷：117
• 期：19
• 页码：9723-9733
• 全文大小：610K
• 年卷期：v.117,no.19(May 16, 2013)
• ISSN：1932-7455

文摘

The sequence of surface reconstructions on GaAs(001), usually observed under As desorption in the temperature range from 450 to 580 掳C, was obtained by atomic hydrogen (AH) reaction with the oxide-covered GaAs(001) surfaces in the temperature range from 420 to 280 掳C. With the decrease in annealing temperature under AH treatment of oxide-covered GaAs(001) surfaces, the reconstructions changed from As-rich (2 脳 4)/c(2 脳 8) at 420 掳C through the intermediate (2 脳 6)/(3 脳 6) at 380 掳C, Ga-stabilized (4 脳 2)/c(8 脳 2) at 350 掳C and (4 脳 6) at 330 掳C, to a very Ga-rich (4 脳 4) at 280 掳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 脳 4) surface structure covered by 螛<sub>Gasub> 鈮?0.8 ML was reconstructed to a new Ga-terminated structure with the symmetry of As-rich (2 脳 4)/c(2 脳 8) surface under vacuum annealing at the temperature higher than 560 掳C. DFT calculations support the existence of the energetically favored Ga-rich (2 脳 4) reconstruction described by the mixed-dimer model, developed for InP(001)-(2 脳 4) surface, and predict the coexistence of (2 脳 4) and (4 脳 4) reconstructions on GaAs(001) at the Ga-rich limit.