| 摘要 |
SiGe quantum wells where the well material has a lowest conduction band energy minimum at k=0 (the Gamma point of the first Brillouin zone) are provided. Quantum well structures that satisfy this condition have "Kane-like" bands at and near k=0 which can provide physical effects useful for various device applications, especially optical modulators. In the Si<SUB>1-x</SUB>Ge<SUB>x </SUB>material system, this condition on the band structure is satisfied for x greater than about 0.7. The quantum well barrier composition may or may not have Kane-like bands. Embodiments of the invention having a surface parallel configuration are especially suitable for use in fiber coupled devices. Such surface parallel devices have light propagating in the plane of the quantum wells, in a device geometry that is preferably not single-mode waveguided.
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