Stark effect, polarizability and electroabsorption in silicon nanocrystals

Abstract

Demonstrating the quantum-confined Stark effect (QCSE) in silicon nanocrystals (NCs) embedded in oxide has been rather elusive, unlike the other materials. Here, the recent experimental data from ion-implanted Si NCs is unambiguously explained within the context of QCSE using an atomistic pseudopotential theory. This further reveals that the majority of the Stark shift comes from the valence states which undergo a level crossing that leads to a nonmonotonic radiative recombination behavior with respect to the applied field. The polarizability of embedded Si NCs including the excitonic effects is extracted over a diameter range of 2.5--6.5 nm, which displays a cubic scaling, $\alpha =c{D}^3$, with $c=2.436\times 10^{-11}$ C/(Vm), where $D$ is the NC diameter. Finally, based on intraband electroabsorption analysis, it is predicted that p-doped Si NCs will show substantial voltage tunability, whereas n-doped samples should be almost insensitive. Given the fact that bulk silicon lacks the linear electro-optic effect as being a centrosymmetric crystal, this may offer a viable alternative for electrical modulation using p-doped Si NCs.

Published version, 7 pages, 7 figures

References in corpus (4)

• Interband, intraband and excited-state direct photon absorption of silicon and germanium nanocrystals embedded in a wide band-gap lattice
• Silicon Nanocrystallites in SiO2 Matrix: The Role of Disorder and Size
• Auger recombination and carrier multiplication in embedded silicon and germanium nanocrystals
• Tight binding formulation of the dielectric response in semiconductor nanocrystals

Cited by in corpus (3)

• Networks of silicon nanowires: a large-scale atomistic electronic structure analysis
• Electron ground state $g$ factor in embedded InGaAs quantum dots: An atomistic study
• dc-switchable and single-nanocrystal-addressable coherent population transfer