Insight into the effects of surface oxidation and carbonization on the electronic properties of silicon quantum dots and silicon slabs: a density functional study

RSC Advances ◽  
2014 ◽  
Vol 4 (105) ◽  
pp. 60948-60952 ◽  
Author(s):  
Yuheng Zeng ◽  
Liang Chen ◽  
Guoqiang Liu ◽  
Hua Xu ◽  
Weijie Song
Keyword(s):  
Quantum Dots ◽  
Electronic Properties ◽  
Density Functional ◽  
Surface Oxidation ◽  
Functional Study ◽  
Silicon Quantum Dots ◽  
Carrier Recombination ◽  
Oxygen Oxidation ◽  
Si Quantum Dots ◽  
Insight Into

In this work, we investigated the effects of surface backbond-oxygen oxidation and surface substitute-carbon carbonization on carrier recombination and transportation of 10-, 12- and 14 Å Si quantum dots (QDs).

Surface Passivation Effect of Hydrogen and Methyl on the Structural and Electronic Properties of Silicon Quantum Dots: Density Functional Calculation

2016 ◽  
Vol 846 ◽  
pp. 375-382 ◽  
Author(s):  
Muhammad Mus-'ab Anas ◽  
Geri Gopir
Keyword(s):  
Quantum Dots ◽  
Band Gap ◽  
Electronic Properties ◽  
Density Functional ◽  
Surface Passivation ◽  
Geometry Optimization ◽  
Point Of View ◽  
Silicon Quantum Dots ◽  
Radiative Relaxation ◽  
Structural And Electronic Properties

We have carried out a series of DFT calculations to investigate changes on the structural and electronic properties of Silicon (Si) quantum dots as a function of surface passivation. In particular, we have study non-polar passivation effect of hydrogen (H) and methyl (CH3) at the surface of quantum dots. From geometry optimization result, we find that clusters with reconstructed surfaces a complete methyl passivation is possible and steric repulsion prevents full passivation of Si dots with unreconstructed surfaces. On the electronic properties point of view, it is noticed for small nanocrystals, the presence of mini-gaps are more pronounced which can limit the non-radiative relaxation of excitons. Obviously, methyl passivation weakly affects the band gap values of silicon quantum dots, while it substantially decreases the band gap and reduce mini-gap appearance compared to hydrogen passivation Si QDs. On the basis of our results we propose that methyl terminated quantum dots may be size selected taking advantage of the reduction on mini-gap and the localization of electron as a function of the cluster size.

Communication: Photoinduced Carbon Dioxide Binding with Surface-Functionalized Silicon Quantum Dots

2018 ◽  
Author(s):  
Oscar A. Douglas-Gallardo ◽  
Cristián Gabriel Sánchez ◽  
Esteban Vöhringer-Martinez
Keyword(s):  
Carbon Dioxide ◽  
Quantum Dots ◽  
Atmospheric Carbon Dioxide ◽  
Density Functional ◽  
Tight Binding ◽  
Carbon Dioxide Concentration ◽  
Research Area ◽  
Silicon Quantum Dots ◽  
Dependent Model ◽  
Photoinduced Charge

<div> <div> <div> <p>Nowadays, the search of efficient methods able to reduce the high atmospheric carbon dioxide concentration has turned into a very dynamic research area. Several environmental problems have been closely associated with the high atmospheric level of this greenhouse gas. Here, a novel system based on the use of surface-functionalized silicon quantum dots (sf -SiQDs) is theoretically proposed as a versatile device to bind carbon dioxide. Within this approach, carbon dioxide trapping is modulated by a photoinduced charge redistribution between the capping molecule and the silicon quantum dots (SiQDs). Chemical and electronic properties of the proposed SiQDs have been studied with Density Functional Theory (DFT) and Density Functional Tight-Binding (DFTB) approach along with a Time-Dependent model based on the DFTB (TD-DFTB) framework. To the best of our knowledge, this is the first report that proposes and explores the potential application of a versatile and friendly device based on the use of sf -SiQDs for photochemically activated carbon dioxide fixation. </p> </div> </div> </div>

Quantum transport, electronic properties and molecular adsorptions in graphene

2021 ◽  
Vol 35 (08) ◽  
pp. 2130001
Author(s):  
Yoshitaka Fujimoto
Keyword(s):  
Electronic Properties ◽  
Quantum Transport ◽  
Density Functional ◽  
Field Effect Transistors ◽  
Electronic Conductivity ◽  
Volume Ratio ◽  
Functional Study ◽  
Sensor Applications ◽  
Sensing Applications ◽  
High Electronic Conductivity

Molecular sensor applications are used in different fields including environmental monitoring and medical diagnosis. Graphene, a single atomic layer consisting of the hexagonally arranged carbon material, is one of the most promising materials for ideal channels in field-effect transistors to be used as electronic sensing applications owing to its lightweight, mechanical robustness, high electronic conductivity and large surface-to-volume ratio. This paper provides a review of molecular adsorptions, electronic properties and quantum transport of graphene based on the first-principles density-functional study. The adsorption properties of environmentally polluting or toxic molecules and electronic transport of graphene are revealed. The possibility of detecting these molecules selectively is also discussed for designing the graphene-based sensor applications.

scholarly journals Wigner molecules in polygonal quantum dots:  A density-functional study

2003 ◽  
Vol 67 (3) ◽  
Author(s):  
E. Räsänen ◽  
H. Saarikoski ◽  
M. J. Puska ◽  
R. M. Nieminen
Keyword(s):  
Quantum Dots ◽  
Density Functional ◽  
Functional Study ◽  
Density Functional Study
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