Shell-Thickness Controlled Semiconductor–Metal Transition in Si–SiC Core–Shell Nanowires

Amato, Michele; Rurali, Riccardo

doi:10.1021/acs.nanolett.5b00670

Cited by 14 publications

(11 citation statements)

References 66 publications

(80 reference statements)

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“…[17][18][19][20] A particular focus has been put on the coreshell interface broadening and the strain relaxation/strain sharing between core and shell. [21][22][23] Moreover, 2D quantum confinement effects and strain band-gap engineering are exploited in order to achieve improved opto-electronic performances [24][25][26][27][28] and thermoelectric efficiency. [29][30][31][32][33][34][35][36][37] Band-gap strain engineering of planar systems structures is efficiently used for ultra-thin Silicon On Insulator (SOI) based devices to provide compressive tensile strain.…”

Section: Introductionmentioning

confidence: 99%

Tailoring Strain and Morphology of Core–Shell SiGe Nanowires by Low-Temperature Ge Condensation

et al. 2017

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Selective oxidation of the silicon element of silicon germanium (SiGe) alloys during thermal oxidation is a very important and technologically relevant mechanism used to fabricate a variety of microelectronic devices. We develop here a simple integrative approach involving vapor-liquid-solid (VLS) growth followed by selective oxidation steps to the construction of core-shell nanowires and higher-level ordered systems with scalable configurations. We examine the selective oxidation/condensation process under nonequilibrium conditions that gives rise to spontaneous formation of core-shell structures by germanium condensation. We contrast this strategy that uses reaction-diffusion-segregation mechanisms to produce coherently strained structures with highly configurable geometry and abrupt interfaces with growth-based processes which lead to low strained systems with nonuniform composition, three-dimensional morphology, and broad core-shell interface. We specially focus on SiGe core-shell nanowires and demonstrate that they can have up to 70% Ge-rich shell and 2% homogeneous strain with core diameter as small as 14 nm. Key elements of the building process associated with this approach are identified with regard to existing theoretical models. Moreover, starting from results of ab initio calculations, we discuss the electronic structure of these novel nanostructures as well as their wide potential for advanced device applications.

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Section: Introductionmentioning

confidence: 99%

Tailoring Strain and Morphology of Core–Shell SiGe Nanowires by Low-Temperature Ge Condensation

et al. 2017

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“…Si NWs can be fabricated with a lot of different large scale techniques which always produce high crystalline, stable and reproducible semiconductor materials (in contrast to carbon nanotubes) that can be easily integrated into current Si technology, iii) the possibility to easily functionalize their oxide surface. As discussed in Section 3, functionalization is an important aspect of Si NWs sensing as chemical or biological modification is often a fundamental requirement for their operation and biocompatibility[141,142,143,144,145,146,150]. Depending on the working principle of the sensor, metallic, covalent or non-covalent functionalization of Si NWs[141,142,151] have been proposed always assuming particular importance for the efficiency of the device, iv) the cylindrical 1D geometry that together with the small size induces electrical and optical properties that can be strongly influenced by minor perturbations.…”

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confidence: 99%

Surface physics of semiconducting nanowires

Amato

Rurali

2016

Progress in Surface Science

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Semiconducting nanowires (NWs) are firm candidates for novel nanoelectronic devices and a fruitful playground for fundamental physics. Ultra-thin nanowires, with diameters below 10 nm, presents exotic quantum effects due to the confinement of the wave functions, e.g. broadening of the electronic band-gap, deepening of the dopant states. However, although several reports of sub-10 nm wires exist to date, the most common NWs have diameters that range from 20 to 200 nm, where these quantum effects are absent or play a very minor role. Yet, the research activity on this field is very intense and these materials still promise to provide an important paradigm shift for the design of emerging electronic devices and different kinds of applications. A legitimate question is then: what makes a nanowire different from bulk systems? The answer is certainly the large surface-to-volume ratio. In this article we discuss the most salient features of surface physics and chemistry in group-IV semiconducting nanowires, focusing mostly on Si NWs. First we review the state-of-the-art of NW growth to achieve a smooth and controlled surface morphology. Next we discuss the importance of a proper surface passivation and its role on the NW electronic properties. Finally, stressing the importance of a large surface-to-volume ratio and emphasizing the fact that in a NW the surface is where most of the action takes place, we discuss molecular sensing and molecular doping.

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“…These large local strains represent a huge departure from the perfect crystal structure and introduce many electronic modes in the band gap, thereby making the gap totally disappear (Figure 4(f)). This particular phenomena has been reported in relatively thinner core-shell Si-SiC NWs and attributed to the relatively huge compressive strain ~9% [18]. It has been shown experimentally that bending increases nanowire conductivity [51], [52], so bandgap decrease and conductivity increase can be correlated.…”

Section: Electronic Transmissionmentioning

confidence: 54%

Moderate bending strain induced semiconductor to metal transition in Si nanowires

Rabbani

Patil

Anantram

2016

Semicond. Sci. Technol.

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Moderate amount of bending strains, ~3% are enough to induce the semiconductor-metal transition in Si nanowires of ~4nm diameter. The influence of bending on silicon nanowires of 1 nm to 4.3 nm diameter is investigated using molecular dynamics and quantum transport simulations.Local strains in nanowires are analyzed along with the effect of bending strain and nanowire diameter on electronic transport and the transmission energy gap. Interestingly, relatively wider nanowires are found to undergo semiconductor-metal transition at relatively lower bending strains.The effect of bending strain on electronic properties is then compared with the conventional way of straining, i.e. uniaxial, which shows that, the bending is much more efficient way of straining to enhance the electronic transport and also to induce the semiconductor-metal transition in experimentally realizable Si nanowires.

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Shell-Thickness Controlled Semiconductor–Metal Transition in Si–SiC Core–Shell Nanowires

Cited by 14 publications

References 66 publications

Tailoring Strain and Morphology of Core–Shell SiGe Nanowires by Low-Temperature Ge Condensation

Tailoring Strain and Morphology of Core–Shell SiGe Nanowires by Low-Temperature Ge Condensation

Surface physics of semiconducting nanowires

Moderate bending strain induced semiconductor to metal transition in Si nanowires

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