Charge Separation via Strain in Silicon Nanowires

Wu, Zhigang; Neaton, Jeffrey B.; Grossman, Jeffrey C.

doi:10.1021/nl9010854

Cited by 131 publications

(107 citation statements)

References 23 publications

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“…C Semiconducting nanowires (NWs) are basic building blocks for the function and integration of nanoscale devices such as nanoswitches, single electron transistors, optoelectronic units, sensors, and solar cells. [1][2][3][4][5][6][7][8][9][10] Silicon nanowires (SiNWs) are prototype semiconducting wires that have attracted a great deal of attention. 11 They have been found to have more advantageous catalytic properties than palladium or gold.…”

mentioning

confidence: 99%

Tunable electronic properties of silicon nanowires under strain and electric bias

Nduwimana

Wang

2014

AIP Advances

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The electronic structure characteristics of silicon nanowires under strain and electric bias are studied using first-principles density functional theory. The unique wire-like structure leads to distinct spatial distribution of carriers, which can be tailored by applying tensile and compressive strains, as well as by an electric bias. Our results indicate that the combined effect of strain and electric bias leads to tunable electronic structures that can be used for piezo-electric devices.

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mentioning

confidence: 99%

Tunable electronic properties of silicon nanowires under strain and electric bias

Nduwimana

Wang

2014

AIP Advances

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“…29 However, the anti-bonding characteristics suggests that the nodal surfaces of the positive and negative values of the wavefunction are perpendicular to the z-direction and a compressive uniaxial strain reduces the distance between the nodal surfaces, therefore kinetic energy associated with the electron transportation between atoms increases. [30][31][32] In contrast, a tensile strain increases the nodal surfaces thus reducing the associated kinetic energy.…”

mentioning

confidence: 99%

Engineering direct-indirect band gap transition in wurtzite GaAs nanowires through size and uniaxial strain

Copple

Ralston

Peng

2012

Applied Physics Letters

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Electronic structures of wurtzite GaAs nanowires in the [0001] direction were studied using first-principles calculations. It was found that the band gap of GaAs nanowires experience a direct-to-indirect transition when the diameter of the nanowires is smaller than ~28 Å. For those thin GaAs nanowires with an indirect band gap, it was found that the gap can be tuned to be direct if a moderate external uniaxial strain is applied. Both tensile and compressive strain can trigger the indirect-to-direct gap transition. The critical strains for the gap-transition are determined by the energy crossover of two states in conduction bands. etc. In particular, GaAs has been considered as a promising channel material for the high speed NMOS beyond Si based technology. GaAs has two different crystal structures zinc blende (ZB) and wurtzite (WZ) phases. In bulk GaAs, ZB phase is energetically more favorable than WZ. In nanoscale, however, WZ phase was observed more often experimentally. Theoretical work,8 including abinitio calculations, has shown that at small size WZ structure is energetically more favorable, [8][9][10] and the interface energy may also facilitate the growth of WZ structure. 11Recent experiments have shown it is possible to grow GaAs nanowires in ZB, 12 WZ, 13 and mixed crystal phases. 14 While bulk GaAs (both ZB and WZ) has a direct band gap, GaAs nanowires may demonstrate an indirect gap when the diameter of nanowire is sufficiently small. 15,16 This band gap transition could fundamentally alter the electronic properties of nanowires. In addition to size, strain has become a routine factor to engineer band gaps of semiconductors in the field of microelectronics. Researchers have theoretically demonstrated the modulated band gap by external strains in a variety of systems such as pure Si 17 and Ge 18and Si/Ge Core-shell nanowires. 19It would be very interesting to investigate strain effects on the band structure of WZ GaAs nanowires and examine if the direct-indirect band gap transition can be engineered for applications.The ab-initio density functional theory (DFT) 20 calculations were carried out using VASP code 21,22 . The DFT local density approximation and the projector-augmented wave potentials 23,24 were used along with plane wave basis sets. The kinetic energy cutoff for the plane wave basis set was chosen to be 300.0 eV. The energy convergence criteria for electronic and ionic iterations are 10 -4 eV and 0.03 eV/Å, respectively. The GaAs nanowires were generated along the [0001] direction (i.e. z-axis) from bulk WZ GaAs with different diameters in the wire cross section (see Figure 1). The dangling bonds on the wire surface are saturated by hydrogen atoms.

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“…The decomposed contributions/coefficients of s, p, d orbitals are listed in Table 4. The VBE (i. e. VB at ) is dominated by a p z character, which suggests that the nodal surfaces of the positive and negative values of the wave-function are perpendicular to the axis of the wire (Leu et al, 2008;Z. G. Wu et al, 2009).…”

Section: Band Gap For Strained Si/ge Core-shell Nanowiresmentioning

confidence: 99%

“…G. Wu et al, 2009). Under a tensile strain, the distance between the nodal surfaces increases, and the kinetic energy associated with the electron transportation between atoms reduces (Z. G. Wu et al, 2009). The same holds true for the VBE energy.…”

Section: Band Gap For Strained Si/ge Core-shell Nanowiresmentioning

confidence: 99%

First Principles Study of Si/Ge Core-Shell Nanowires ---- Structural and Electronic Properties

Peng¹,

Tang²,

Logan³

2011

Nanowires - Fundamental Research

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Charge Separation via Strain in Silicon Nanowires

Cited by 131 publications

References 23 publications

Tunable electronic properties of silicon nanowires under strain and electric bias

Tunable electronic properties of silicon nanowires under strain and electric bias

Engineering direct-indirect band gap transition in wurtzite GaAs nanowires through size and uniaxial strain

First Principles Study of Si/Ge Core-Shell Nanowires ---- Structural and Electronic Properties

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