Donor Wave Functions Delocalization in Silicon Nanowires: The Peculiar [011] Orientation

The localization of the donor electron wave function can be of key importance in various silicon applications, since for example it determines the interactions between neighboring donors. Interestingly, the physical confinement of the electrons in quasi-one-dimensional nanostructures, like silicon nanowires, noticeably affects this property. Using fully ab initio calculations, we show that the delocalization of the donor electron wave function along the axis of a nanowire is much greater in [011] oriented nanowires for phosphorus and selenium donors. We also demonstrate that its value can be controlled by applying a compressive or tensile uniaxial strain. Finally, we discuss the implications of these features from both an experimental and a theoretical point of view

Phase Stabilization of Al:HfO₂ Grown on In_<i>x</i>Ga_1–<i>x</i>As Substrates (<i>x</i> = 0, 0.15, 0.53) via Trimethylaluminum-Based Atomic Layer Deposition

Al:HfO₂ is grown on III–V compound substrates by atomic layer deposition after an in situ trimethylaluminum-based preconditioning treatment of the III–V surface. After post-deposition rapid thermal annealing at 700 °C, the cubic/tetragonal crystalline phase is stabilized and the chemical composition of the stack is preserved. The observed structural evolution of Al:HfO₂ on preconditioned III–V substrates shows that the in-diffusion of semiconductor species from the substrate through the oxide is inhibited. Al-induced stabilization of the Al:HfO₂ crystal polymorphs up to 700 °C can be used as a permittivity booster methodology with possibly important implications in the stack scaling issues of high-mobility III–V based logic applications

Getting through the Nature of Silicene: An sp²–sp³ Two-Dimensional Silicon Nanosheet

By combining experimental techniques with ab initio density functional theory calculations, we describe the Si/Ag(111) 2D systems in terms of a sp²–sp³ form of silicon characterized by a vertically distorted honeycomb lattice provided by the constraint imposed by the substrate. The Raman spectrum reflects the multihybridized nature of the 2D Si nanosheets (NSs) resulting from a buckling-induced distortion of a purely sp² hybridized structure. We show that vibrational and electronic properties of 2D Si-NSs are tightly linked to the buckling arrangement