Optical TCAD on the Net: A tight-binding study of inter-band light transitions in self-assembled InAs/GaAs quantum dot photodetectors

Ryu, Hoon; Nam, Dukyun; Ahn, Bu-Young; Lee, Jongsuk Ruth; Cho, Kumwon; Lee, Sunhee; Klimeck, Gerhard; Shin, Mincheol

doi:10.1016/j.mcm.2012.11.024

Cited by 4 publications

(1 citation statement)

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“…The resulting wavefunctions and energy levels are used to determine other device related parameters such as energy gaps, momentum matrix elements, and optical transition rates. 52,82 The spontaneous emission rate G(o) between an excited state and the ground state is calculated using Fermi's golden rule,…”

Section: Introductionmentioning

confidence: 99%

Effect of strain on the electronic and optical properties of Ge–Si dome shaped nanocrystals

Neupane

Rahman

Lake

2015

Phys. Chem. Chem. Phys.

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The effects of strain and confinement on the energy levels and emission spectra of dome-shaped, Ge-core-Si-shell nanocrystals (NCs) with diameters ranging from 5 to 45 nm are investigated with atomistic models. For NCs with base diameters ≥15 nm, the strain-induced increase in the energy gap is ∼100 meV. The increase in the energy gap is primarily the result of the downward shift in the occupied states confined in the Ge core. The fundamental energy gap varies from 960 meV to 550 meV as the NC diameter increases from 5 nm to 45 nm. Confinement and strain break the degeneracy of the lowest excited state and split it into two states separated by a few meV. For the smaller NCs, one of these states can be localized in the Si core and the other state can be in the Si cap. For diameters ≥20 nm, both of these states are localized in the Si cap. The electronic states are calculated using an atomistic sp(3)d(5)s* tight-binding model including spin-orbit coupling, and geometry relaxation is performed using a valence force field model.

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Section: Introductionmentioning

confidence: 99%