Si Nanowires as Sensors:  Choosing the Right Surface

Leão, Cedric Rocha; Fazzio, A.; Silva, Antônio J. R. da

doi:10.1021/nl0628697

Cited by 42 publications

(54 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The facet effect has been widely discussed in recent years and the general conclusion has been made that different facets have different contributions to the electronic properties. 21,23 However, in Li insertion investigations, we find that the binding energy of interstitial Li is almost independent of facets, and the E b values can be quite different even in closed S sites on the same facet. That variety of binding energies is caused by distinct local environments around different S sites, including the number of nearest or second nearest Si atoms, the neighboring Si atom and H atom configuration, and its positional relationship with the Li atom.…”

Section: ∆F ) F[li/sinw] -F[li] -F[sinw]mentioning

confidence: 77%

Lithium Insertion In Silicon Nanowires: An ab Initio Study

et al. 2010

View full text Add to dashboard Cite

The ultrahigh specific lithium ion storage capacity of Si nanowires (SiNWs) has been demonstrated recently and has opened up exciting opportunities for energy storage. However, a systematic theoretical study on lithium insertion in SiNWs remains a challenge, and as a result, understanding of the fundamental interaction and microscopic dynamics during lithium insertion is still lacking. This paper focuses on the study of single Li atom insertion into SiNWs with different sizes and axis orientations by using full ab initio calculations. We show that the binding energy of interstitial Li increases as the SiNW diameter grows. The results show that the Li surface diffusion has a much higher chance to occur than the surface to core diffusion, which is consistent with the experimental observation that the Li insertion in SiNWs is layer by layer from surface to inner region. After overcoming a large barrier crossing surface-to-intermediate region, the diffusion toward center has a higher possibility to occur than the inverse process.KEYWORDS Silicon nanowire, anode, lithium ion battery, ab initio simulation, binding energy, diffusion barrier S ilicon nanowires (SiNWs) have attracted much attention for many applications, such as field effect transistors, 1-3 nanosensors, 4-6 and solar cells. 7-9 These applications take advantage of the high crystallinity and/or large surface area of SiNWs. Excitingly, SiNWs have recently been demonstrated as ultrahigh capacity lithium ion battery negative electrodes, 10 which opens up exciting opportunities for energy storage devices. Silicon has the highest known specific charge capacity (4200 mAh/g), which is ∼10 times larger than that of the graphite carbon used in existing technology. 11 However, the 300% volume expansion upon lithium insertion has caused pulverization or mechanical fracture in micrometer particle and bulk Si. The success of using SiNWs lies in their facile strain relaxation without mechanical breaking, efficient electron transport along their long axis, and large lithium ion flux due to their large surface area. Since the important demonstration of SiNWs as lithium ion battery anodes, a variety of Si nanostructure morphologies has been demonstrated to overcome the mechanical breaking issues and perform well as anodes. Si nanostructures shown to exhibit good performance include crystallineamorphous core-shell Si NWs, 12 carbon-amorphous Si core-shell NWs, 13 Si nanotubes, 14 porous Si particles, 15 and an ordered macroporous carbon-Si composite. 16 However, experimental investigation has mainly been focused on electrochemical cycling of Si-Li compounds and phase transitions during Li insertion; all the Si-Li phases were found when the system is rich in Li atoms. 10,17 Although the Si-Li compound can be accurately analyzed, the fundamental interaction between Li and Si atoms and the microscopic dynamic process during Li insertion still remain unknown.On the theoretical side, there have been studies on electronic properties, 18-20 surface effects, 21,22 B or P...

show abstract

Section: ∆F ) F[li/sinw] -F[li] -F[sinw]mentioning

confidence: 77%

Lithium Insertion In Silicon Nanowires: An ab Initio Study

et al. 2010

View full text Add to dashboard Cite

show abstract

“…Silicon nanowires have recently been utilized in many device applications such as thermoelectric materials [3], solar cells [4], sensors [5], as well as field-effect transistor [6], attributing to the rapid development of synthetic and fabrication technologies. Silicon monatomic chain (SiMC) is the ultimate silicon nanowire and provides a promising concept for the bottom-up approach to nanoelectronics.…”

Section: Introductionmentioning

confidence: 99%

Negative differential resistance behavior of silicon monatomic chain encapsulated in carbon nanotubes

Zhang¹,

Wang²,

Zhao³

2012

Computational Materials Science

View full text Add to dashboard Cite

a b s t r a c tUsing nonequilibrium Green's functions in combination with density-functional theory (DFT), we investigated the electronic transport properties of the silicon monatomic chains (SiMCs) with different geometries which were induced by the encapsulation of the carbon nanotubes (CNTs). The encapsulated SiMCs, which were put inside (5,5), (6,6), (7,7) and (8,8) hydrogenated armchair CNTs, were coupled to two Au (1 0 0) nanoscale electrodes. The electronic transport property of an isolated finite SiMC was also studied to serve as a reference to our calculations. As the diameter of CNTs increases, the geometry structures of SiMCs changed. Calculated results show that the current-voltage (I-V) characteristics depend sensitively on the geometry structures of SiMCs and can be controlled by the size-selective encapsulation. Negative differential resistance (NDR) phenomena were observed within certain bias voltage ranges. A detailed analysis of the origin of NDR was carried out with the transmission spectrum, the spatial distribution of frontier molecular orbitals and the molecular projected self-consistent Hamiltonian (MPSH) states taken into consideration. These results indicated that the size-selective encapsulation of SiMCs in CNTs can become a possible candidate for designing the silicon-based nanoelectronic devices.

show abstract

“…Primeiro, medimos o peso relativo de grupos distintos dé atomos na composição do topo da banda de valência e base da banda de condução em nanofios pristinos, ou seja, compostos apenas deátomos de Si com superfícies passivadas por hidrogênio. Em seguida, efetuamos análises semelhantes em fios nos quais geramos de fato perturbações em suas superfícies através da adsorção de um radical de NH 2 [26]. Por fim, efetuamos cálculos de transporte eletrônico em fios possuindo radicais NH 2 em suas diferentes facetas.…”

Section: Propostas Deste Trabalhounclassified

“…construídas, essa variação nas energias de formação da impureza no sítio central indica a relevância dos estados de superfície nas propriedades eletrônicas dos fios como um todo, conforme já havíamos discutido no capítulo anterior e na referência [26]. Outra constatação interessante com relação aos dados apresentados na tabela 5.1 diz respeito a energia de formação do defeito no centro do fio totalmente passivado e quando há uma ligação pendente em um dos silícios na superfície.…”

Section: Energias De Formação E Estruturas Eletrônicasunclassified

“…5.3 Na ref. [26], descrita no capítulo anterior, demonstramos que de acordo com a maneira como osátomos se arranjam nas superfícies dos fios, estas podem ser extremamente ativas ou quase inertes no que diz respeito a induzir perturbações na estrutura eletrônica dos fios, sobretudo nos estados em torno do gap de energia. Desta forma, a superfície (001) canted tem pouca participação na formação dos estados de borda dos fios, enquanto as superfícies (001) simétrica e (111) mono-hidrogenada tem peso grande na formação destes estados e portanto são vias importantes para se induzir alterações na estrutura eletrônica dos NWs.…”

Si Nanowires as Sensors: Choosing the Right Surface

Cited by 42 publications

References 23 publications

Lithium Insertion In Silicon Nanowires: An ab Initio Study

Lithium Insertion In Silicon Nanowires: An ab Initio Study

Negative differential resistance behavior of silicon monatomic chain encapsulated in carbon nanotubes

Propriedades eletrônicas de nanofios semicondutores

Contact Info

Product

Resources

About