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

Copple, Andrew; Ralston, Nathaniel; Peng, Xihong

doi:10.1063/1.4718026

Cited by 40 publications

(42 citation statements)

References 33 publications

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“…This linear shift of energy is not unique to phosphorene. It is also observed in other semiconducting nanostructures [28,29,[31][32][33][34][35][36][37][38][51][52][53][54].…”

Section: E Strain Effect On the Near-band-edge Orbitalsmentioning

confidence: 61%

“…This mechanism has been applied successfully in many other semiconductor nanostructures [28,29,[31][32][33][34][35][36][37][38]. Effective masses of charge carriers (thus carrier mobility) were also found to be drastically tuned by strain.…”

Section: /V·smentioning

confidence: 85%

“…This detailed analysis on the direct-indirect band gap transition is crucial for optical applications of phosphorene. For example, Peng and Copple at Arizona State University predicted a similar direct-indirect band gap transition in GaAs nanowires with uniaxial strains [28,29] and the gap transition was observed in a recent experiment [30] in which the luminescence of GaAs nanowires can be switched on and off under the influence of a uniaxial stress.…”

Section: /V·smentioning

confidence: 96%

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Strain-engineered direct-indirect band gap transition and its mechanism in two-dimensional phosphorene

2014

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Recently fabricated two-dimensional phosphorene crystal structures have demonstrated great potential in applications of electronics. In this paper, strain effect on the electronic band structure of phosphorene was studied using first-principles methods including density functional theory (DFT) and hybrid functionals. It was found that phosphorene can withstand a tensile stress and strain up to 10 N/m and 30%, respectively. The band gap of phosphorene experiences a direct-indirect-direct transition when axial strain is applied. A moderate −2% compression in the zigzag direction can trigger this gap transition. With sufficient expansion (+11.3%) or compression (−10.2% strains), the gap can be tuned from indirect to direct again. Five strain zones with distinct electronic band structure were identified, and the critical strains for the zone boundaries were determined. Although the DFT method is known to underestimate band gap of semiconductors, it was proven to correctly predict the strain effect on the electronic properties with validation from a hybrid functional method in this work. The origin of the gap transition was revealed, and a general mechanism was developed to explain energy shifts with strain according to the bond nature of near-band-edge electronic orbitals. Effective masses of carriers in the armchair direction are an order of magnitude smaller than that of the zigzag axis, indicating that the armchair direction is favored for carrier transport. In addition, the effective masses can be dramatically tuned by strain, in which its sharp jump/drop occurs at the zone boundaries of the direct-indirect gap transition.

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“…This linear shift of energy is not unique to phosphorene. It is also observed in other semiconducting nanostructures [28,29,[31][32][33][34][35][36][37][38][51][52][53][54].…”

Section: E Strain Effect On the Near-band-edge Orbitalsmentioning

confidence: 61%

Section: /V·smentioning

confidence: 85%

Section: /V·smentioning

confidence: 96%

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Strain-engineered direct-indirect band gap transition and its mechanism in two-dimensional phosphorene

2014

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“…This band alignment imparts interesting optical properties to WZ crystals: the conduction and valence band wavefunctions have a strong overlap at the G-point, but light emission is weak because of symmetry reasons. Further ab-initio calculations, performed on very small nanowires, highlighted the possibility of inducing indirect bandgap configuration in GaAs WZ crystals 29,30 .…”

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confidence: 99%

Inducing a direct-to-pseudodirect bandgap transition in wurtzite GaAs nanowires with uniaxial stress

et al. 2014

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Many efficient light-emitting devices and photodetectors are based on semiconductors with, respectively, a direct or indirect bandgap configuration. The less known pseudodirect bandgap configuration can be found in wurtzite (WZ) semiconductors: here electron and hole wave-functions overlap strongly but optical transitions between these states are impaired by symmetry. Switching between bandgap configurations would enable novel photonic applications but large anisotropic strain is normally needed to induce such band structure transitions. Here we show that the luminescence of WZ GaAs nanowires can be switched on and off, by inducing a reversible direct-to-pseudodirect band structure transition, under the influence of a small uniaxial stress. For the first time, we clarify the band structure of WZ GaAs, providing a conclusive picture of the energy and symmetry of the electronic states. We envisage a new generation of devices that can simultaneously serve as efficient light emitters and photodetectors by leveraging the strain degree of freedom.

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“…AGNRs have been predicted to own much better electromechanical applications [35] than zigzag-edge GNRs, since the external stress may induce interesting MST in AGNRs. The reactive edges of the asymmetric AGNRs have been demonstrated to be more sensitive to external strain [36], and the uniaxial strains may be effective in modulating the band gap of GaAs nanowires [37]. Furthermore, Bhattacharya et al [38] have investigated the band-gap variation of AGNRs in way of the first-principles calculation, except for the strain and edge passivation-induced energy gap [39] and work function [40] variations for AGNRs.…”

Section: Introductionmentioning

confidence: 98%

Effect of edge chemistry doping on the transport and optical properties for asymmetric armchair-edge graphene nanoribbons under a uniaxial strain

et al. 2015

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The effect of edge n-type nitrogen (N) and p-type oxygen (O) doping on the transport and optical properties for asymmetric 6-and 8-armchair-edge graphene nanoribbons (AGNRs) under a uniaxial strain has been demonstrated in the method of the first-principles density functional theory combined with nonequilibrium Green's function. The transmission spectra and current-voltage (I-V) curves of the semiconducting 6-and metallic 8-AGNRs have been found to be qualitatively unchanged as the uniaxial strain along the armchair edge (Ac-strain), while the quantitative variations come from the mutual actions of the strain and edge doping. However, the observed semiconductor-metal transition and metal-semiconductor transition in the transport properties for 6-and 8-AGNRs should be mainly from the resonance scattering of the doping edges when the external strain is applied along the zigzag edge (Zz-strain). The distinct variation trends of the system transport properties are well confirmed from the optical absorption spectra. It is believed that the obtained results are of importance in exploiting chemistry at the reactive edges of the asymmetric AGNRs and strain engineering of the nanoelectronic/optoelectronic devices based on AGNRs.

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

Cited by 40 publications

References 33 publications

Strain-engineered direct-indirect band gap transition and its mechanism in two-dimensional phosphorene

Strain-engineered direct-indirect band gap transition and its mechanism in two-dimensional phosphorene

Inducing a direct-to-pseudodirect bandgap transition in wurtzite GaAs nanowires with uniaxial stress

Effect of edge chemistry doping on the transport and optical properties for asymmetric armchair-edge graphene nanoribbons under a uniaxial strain

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