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Presents information on a study which measured the electrical properties of metal/β-FeSi[sub2]/Si double junctions and the optical properties of β-FeSi[sub2]/Si structures. Preparation of epitaxial iron silicide films; Optical measurements; Capacitance measurements; Observation on the ac equivalent circuit for low frequencies; Use of admittance spectroscopy to characterize heterojunctions and obtain energies of impurity levels or band offsets.

The very early stages of Pb deposition on Si(111)-(7×7) surfaces have been investigated in real time by scanning tunneling microscopy. Variable temperature measurements combined with unusually long periods of imaging time have enabled us to observe that single Pb atoms are highly mobile within each half of the 7×7 unit cell. Individual jumps of single atoms between different half-cells have been resolved as well as the formation of atom pairs as a result. An activation energy of 0.64±0.07 eV has been measured for the diffusion of single atoms between different half-cells. Pb atom pairs are also mobile inside half-cells at much slower rates than single atoms. An activation energy of 0.40±0.04 eV has been measured for this process. [ABSTRACT FROM AUTHOR]

Semiconducting βFeSi2 has been successfully grown on a Si (111) substrate. It has been proven that under ultrahigh vacuum conditions, the solid phase epitaxy temperature can be lowered to ∼800 K, where only the βFeSi2 phase is stabilized. The disilicide formation was monitored in situ by various surface-sensitive techniques such as low-energy electron diffraction, Auger electron spectroscopy, and ultraviolet photoelectron spectroscopy. The epitaxial relationships were ascertained by transmission electron diffraction and microscopy including high-resolution cross-sectional image. The results show the epitaxy of βFeSi2 (110) and (101) planes parallel to the Si (111) plane. The disilicide-silicon heterojunction displays an atomically abrupt interface. [ABSTRACT FROM AUTHOR]