Formation of interfacial phases in the epitaxial growth of Sb on
Si(111)-7 ¥ 7 reconstructed surface*
Vinod Kumar Paliwal1,2, A. G. Vedeshwar2, and
S. M. Shivaprasad1,**
1Surface Physics Group, National Physical Laboratory,
New Delhi 110 012, India; 2Department of Physics and Astrophysics, University
of Delhi, Delhi 110 007, India
Abstract: Understanding the evolution of the Sb/Si(111) interface
is of great interest in the formation of devices of nanodimensions.
We have undertaken in situ (10-11
torr) studies of Sb adsorption (at room temperature) and its desorption
on the 7 X 7 reconstructed
Si(111) surface, by complementary techniques such as X-ray photoelectron
spectroscopy (XPS), Auger electron spectroscopy (AES), low-energy electron
diffraction (LEED), and electron energy loss spectroscopy (EELS). For
room-temperature (RT) Sb adsorption, the overlayer grows in the Frank
van der Merwe mode, forming an interface state of d(7
X 7) in the submonolayer
Sb coverage regime. Adsorption of 1.0 monolayer (ML) Sb at RT shows
an abrupt shift of 0.8 eV in the peak position of the Sb 3d5/2
transition owing to band-bending caused by a metallic (7 X
7) to a semiconducting (1 X
1) surface phase transformation. Changes observed in full width
at half-maximum (fwhm) and Sb 3d3/2 and 3d5/2
branching ratio are discussed. Thermal annealing experiments provide
evidence for agglomeration of Sb islands, before the multilayer and
monolayer desorption. During this desorption process, we have observed
two novel surface phases of (5 X
5) at 0.4 ML and (53
X 53R30°)
at 0.2 ML, stable at higher temperatures.
* Special Topic Issue on the Theme
of Nanostructured Advanced Materials
**Corresponding author
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