Composition and structure of chemically prepared GaAs(1 1 1)A and (1 1 1)B surfaces |
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Authors: | OE Tereshchenko VL Alperovich AS Terekhov |
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Institution: | Institute of Semiconductor Physics, Novosibirsk State University, Lavrentiev Avenue 13, 630090 Novosibirsk, Russian Federation |
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Abstract: | The (1 1 1)A and (1 1 1)B surfaces of GaAs chemically treated in HCl-isopropanol solution (HCl-iPA) and annealed in vacuum were studied by means of X-ray photoelectron spectroscopy (XPS), low-energy electron diffraction (LEED) and electron energy loss spectroscopy (EELS). To avoid uncontrolled contamination, chemical treatment and sample transfer into UHV were performed under pure nitrogen atmosphere. The HCl-iPA treatment removes gallium and arsenic oxides, with about 0.5-3 ML of elemental arsenic being left on the surface, depending on the crystallographic orientation. With the increase of the annealing temperature, a sequence of reconstructions were identified by LEED: (1 × 1) and (2 × 2) on the (1 1 1)A surface and (1 × 1), (2 × 2), (1 × 1), (3 × 3), (√19 × √19) on the (1 1 1)B surface. These sequences of reconstructions correspond to the decrease of surface As concentration. The structural properties of chemically prepared GaAs(1 1 1) surfaces were found to be similar to those obtained by decapping of As-capped epitaxial layers. |
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Keywords: | Gallium arsenide Polar crystal surfaces Chemical passivation Low energy electron diffraction Photoelectron spectroscopy |
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