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The band offsets for strained Si 1−x−y Ge x C y layers grown on Si(001) substrate and for strained Si 1−x Ge x layers grown on fully relaxed Si 1−z Ge z virtual substrates are estimated. The hydrostatic strain, the uniaxial strain and the intrinsic chemical effect of Ge and C are considered separately. Unknown material parameters relative to the latter effect are chosen to give the best agreement with the available experimental results for Si 1−x Ge x and Si 1−y C y layers on Si. As a general trend concerning carrier confinement opportunities, it is found that a compressive strain is required to obtain a sizeable valence band offset, while a tensile strain is needed to obtain a conduction band discontinuity. In most cases the strain is responsible for a bandgap narrowing with respect to that of the substrate. The obtained results are in very good agreement with available experimental determinations of band offsets and bandgap changes for ternary alloys on Si(001).

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The purpose of this article is to present an accurate way, based on a physical description, to simulate

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This article presents a self-consistent Poisson–Schrödinger calculation based on either the Hartree or the density functional theory for silicon quantum dots surrounded by silicon dioxide. These models can treat any shape of confining potential and take into account the different effective masses and permittivities of the materials. The energy states and the equivalent capacitance of a single dot are then determined as a function of dot radius and number of confined electrons. Finally, the Hartree approach and the density functional theory are compared.