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The semiconducting beta-FeSi2 has a wide variety of silicon based applications. Many transmission and reflection electron-diffraction techniques are used in the study of heteroepitaxial film growth on silicon. The complicated crystal structure of the material causes difficulty in the experimental investigation. Hence, a theoretical reference number is given for the fundamental electron diffraction pattern and is illustrated with a broad range of experimentally determined patterns.

We present calculations of band discontinuities for Si[sub 1-x]Ge[sub x]/Si[sub 1-y]Ge[sub y] strained/relaxed heterointerfaces using the model-solid theory. From the obtained results, we then report a numerical simulation of the conduction-band diagram of a resonant tunneling diode in the Si/Si[sub 1-y]Ge[sub y] system by solving self-consistently Schrödinger and Poisson equations with and without an applied electric field. An analysis of the Stark effect was made in the investigated heterostructure. Two main features have been extrapolated: (i) two sheets of a two-dimensional electron gas are created, leading to a resonant tunneling through the structure, (ii) a charge transfer can occur due to this tunneling effect. In addition, it is found that this charge transfer is highly sensitive to temperature and tends to saturate as the applied electric field increases. [ABSTRACT FROM AUTHOR]

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Examines the surface electron-diffraction patterns of Β-iron-silicon films epitaxially grown on silicon. Crystal structure of the films; Propensity for formation of epitaxial variants by rotation twinning; Use of in situ transmission reflection high-energy electron diffraction from rough but epitaxial films.

The calculations of band discontinuities for Si(sub 1-x)Ge(sub x)/Si(sub 1-y)Ge(sub y) strained/relaxed heterointerfaces using the model-solid theory are presented. The Stark effect on the quantum-confined subbands and the charge transfer under a uniform applied electric field is investigated and the effects of temperature are discussed.

This work deals with the optoelectronic properties of heterostructures built on type II Si1-xGex/Si strained quantum wells grown on relaxed Si1-yGey/Si (001) pseudo-substrates. To limit the intrinsic problem due to the real-space indirect nature of the interface, we propose and model three heterostructures having three different potential profiles of the valence and conduction bands which consist in various arrangements of Si and Si1-xGex barriers of different Ge contents. The proposed stacks are designed in a pragmatic way for a pseudomorphic growth on relaxed Si1-yGey assuming individual layer thickness being smaller than the known critical thickness and an overall compensation of the strain. Variation of thickness and compositions (x>y) permits to optimize i) the quantum confinement of electrons and heavy-hole levels and ii) the wave function's overlap and the out-of-plane oscillator strength. The optimum parameters satisfy a fundamental emission at a key 1.55 μm wavelength below the absorption edge of each layer constitutive of the stacks. A comparison between the characteristics of the three heterostructures brings out the superior advantages of the W architecture. [ABSTRACT FROM AUTHOR]

Ultrathin films (<=50 monolayers) of Co have been deposited on atomically clean 7×7 Si(111) surfaces at room temperature and characterized by in situ surface techniques such as Auger electron spectroscopy and low-energy electron diffraction. Formation of a boundary CoSi2-like phase is surprisingly found at a very low coverage range (<=4 monolayers) as evidenced by low-temperature transport measurements (resistivity and Hall effect) and also by cross-sectional high-resolution transmission electron microscopy. [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]