Defects Responsible for the Hole Gas in Ge/Si Core−Shell Nanowires

Park, Ji-Sang; Ryu, Byungki; Moon, Chang-Youn; Chang, Kee-Joo

doi:10.1021/nl9029972

Cited by 51 publications

(55 citation statements)

References 41 publications

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“…It is found that edge DB defects are much more probable than surface DB defects in silicon nanowires. [79][80][81][82] Therefore, it is necessary to investigate the sensing capability of a SiNR with an edge DB defect. To this end, a hydrogen atom is removed from one silicone edge atom, and only the gas adsorption above the DB defect is tested.…”

Section: Resultsmentioning

confidence: 99%

A theoretical study of gas adsorption on silicene nanoribbons and its application in a highly sensitive molecule sensor

2016

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Inspired by the recent successes in the development of two-dimensional based gas sensors capable of single gas molecule detection, we investigate the adsorption of gas molecules (N2, NO, NO2, NH3, CO, CO2, CH4, SO2, and H2S) on silicene nanoribbons (SiNRs) using density functional theory (DFT) and nonequilibrium Green's function (NEGF) methods. The most stable adsorption configurations, adsorption sites, adsorption energies, charge transfer, quantum conductance modulation, and electronic band structures of all studied gas molecules on SiNRs are studied. Our results indicate that NO, NO2, and SO2 are chemisorbed on SiNRs via strong covalent bonds, suggesting its potential application for disposable gas sensors. In addition, CO and NH3 are chemisorbed on SiNRs with moderate adsorption energy, alluding to its suitability as a highly sensitive gas sensor. The quantum conductance is detectably modulated by chemisorption of gas molecules which can be attributed to the charge transfer from the gas molecule to the SiNR. Other studied gases are physisorbed on SiNRs via van der Waals interactions. It is also found that the adsorption energies are enhanced by doping SiNRs with either B or N atom. Our results suggest that SiNRs show promise in gas molecule sensing applications.

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Section: Resultsmentioning

confidence: 99%

A theoretical study of gas adsorption on silicene nanoribbons and its application in a highly sensitive molecule sensor

2016

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“…A promising alternative to the III-V compounds are Ge/Si core/shell nanowires, which can be grown nuclear-spin-free. The valence band offset at the Ge/Si interface is large, ∼ 0.5 eV, so that holes accumulate naturally in the Ge core without the need for dopants [206,207]. High mobilities [196] and very long mean free paths [206] have been observed, along with a highly coherent charge transport seen through proximity-induced superconductivity [208].…”

Section: Quantum Dots In Nanowiresmentioning

confidence: 99%

Prospects for Spin-Based Quantum Computing in Quantum Dots

Kloeffel

Loss

2013

Annu. Rev. Condens. Matter Phys.

396

410

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Experimental and theoretical progress toward quantum computation with spins in quantum dots (QDs) is reviewed, with particular focus on QDs formed in GaAs heterostructures, on nanowire-based QDs, and on self-assembled QDs. We report on a remarkable evolution of the field where decoherence -one of the main challenges for realizing quantum computers -no longer seems to be the stumbling block it had originally been considered. General concepts, relevant quantities, and basic requirements for spin-based quantum computing are explained; opportunities and challenges of spin-orbit interaction and nuclear spins are reviewed. We discuss recent achievements, present current theoretical proposals, and make several suggestions for further experiments.

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“…In Ge/Si core/shell NWs, which recently attracted attention, the shell is beneficial for several reasons. In particular, it provides a large valence band offset at the interface, leading to a strongly confined hole gas inside the Ge core without the need for dopants [9,10].…”

Section: Introductionmentioning

confidence: 99%

Acoustic phonons and strain in core/shell nanowires

2014

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We study theoretically the low-energy phonons and the static strain in cylindrical core/shell nanowires (NWs). Assuming pseudomorphic growth, isotropic media, and a force-free wire surface, we derive algebraic expressions for the dispersion relations, the displacement fields, and the stress and strain components from linear elasticity theory. Our results apply to NWs with arbitrary radii and arbitrary elastic constants for both core and shell. The expressions for the static strain are consistent with experiments, simulations, and previous analytical investigations; those for phonons are consistent with known results for homogeneous NWs. Among other things, we show that the dispersion relations of the torsional, longitudinal, and flexural modes change differently with the relative shell thickness, and we identify new terms in the corresponding strain tensors that are absent for uncapped NWs. We illustrate our results via the example of Ge/Si core/shell NWs and demonstrate that shell-induced strain has large effects on the hole spectrum of these systems.

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Defects Responsible for the Hole Gas in Ge/Si Core−Shell Nanowires

Cited by 51 publications

References 41 publications

A theoretical study of gas adsorption on silicene nanoribbons and its application in a highly sensitive molecule sensor

A theoretical study of gas adsorption on silicene nanoribbons and its application in a highly sensitive molecule sensor

Prospects for Spin-Based Quantum Computing in Quantum Dots

Acoustic phonons and strain in core/shell nanowires

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