A Story Told by a Single Nanowire: Optical Properties of Wurtzite GaAs

Ahtapodov, Lyubomir; Todorović, Jelena; Olk, Phillip; Mjåland, Terje Sund; Slåttnes, Patrick; Dheeraj, Dasa L.; Helvoort, Antonius T. J. van; Fimland, B. O.; Weman, H.

doi:10.1021/nl3025714

Cited by 102 publications

(123 citation statements)

References 29 publications

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“…The band bending due to induced space charge by spatially separated electrons and holes, typical in type II quantum well, has also been discussed in the literature [12,16]. In polytype NWs inclusion of stacking fault/twinning in the crystal structure, the twin density and periodicity are shown to be reflected in optical transitions in these systems [8,12,17].…”

Section: Introductionmentioning

confidence: 98%

Strain-induced band alignment in wurtzite/zinc-blende InAs heterostructured nanowires

et al. 2015

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We study band alignment in wurtzite-zincblende polytype InAs heterostructured nanowires using temperature dependent resonance Raman measurements. Nanowires having two different wurtzite fractions are investigated. Using visible excitation wavelengths in resonance Raman measurements, we probe the electronic band alignment of these semiconductor nanowires near a high symmetry point of the Brillouin zone (E 1 gap). The strain in the crystal structure, as revealed from the shift of the phonon mode, explains the observed band alignment at the wurtzite-zincblende interface. Our experimental results are further supported by electronic structure calculations for such periodic heterostructured interface.

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Section: Introductionmentioning

confidence: 98%

Strain-induced band alignment in wurtzite/zinc-blende InAs heterostructured nanowires

et al. 2015

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“…Precise control of the morphology 12 and crystal structure 13 have made it possible to grow pure single-crystal wurtzite (WZ) nanowires, not available in bulk or thin-film form 14,15 . WZ crystals are characterized by a peculiar band structure, shown in Fig.…”

mentioning

confidence: 99%

“…After considerable experimental effort [20][21][22][23][24][25] , measurements were able to precisely define the value of the energy bandgap 14,26 , but the energy difference between the two conduction states could not be determined. Indirect measurements merely suggested hints of their energetic proximity 14 . Theoretical investigations addressing this topic have failed to provide a conclusive answer.…”

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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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“…However, other researchers argued for a pseudodirect bandgap, where the dark conduction band is the lowest conduction band. 13,14 In comparison with their NW counterpart, WZ single QDs have not been found in III-V non-nitride semiconductors. WZ GaAs QDs may have an indirect bandgap transition due to the spatial quantum confinement effects, which will further shift up relative to .…”

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confidence: 99%

Zinc-blende and wurtzite GaAs quantum dots in nanowires studied using hydrostatic pressure

et al. 2015

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We report both zinc-blende (ZB) and wurtzite (WZ) crystal phase self-assembled GaAs quantum dots (QDs) embedding in a single GaAs/AlGaAs core-shell nanowires (NWs). Optical transitions and single-photon characteristics of both kinds of QDs have been investigated by measuring photoluminescence (PL) and time-resolved PL spectra upon application of hydrostatic pressure. We find that the ZB QDs are of direct band gap transition with short recombination lifetime (~1 ns) and higher pressure coefficient (75-100 meV/GPa). On the contrary, the WZ QDs undergo a direct-to-pseudodirect bandgap transition as a result of quantum confinement effect, with remarkably longer exciton lifetime (4.5-74.5 ns) and smaller pressure coefficient (28-53 meV/GPa). These fundamentally physical properties are further examined by performing state-of-the-art atomistic pseudopotential calculations.

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A Story Told by a Single Nanowire: Optical Properties of Wurtzite GaAs

Cited by 102 publications

References 29 publications

Strain-induced band alignment in wurtzite/zinc-blende InAs heterostructured nanowires

Strain-induced band alignment in wurtzite/zinc-blende InAs heterostructured nanowires

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

Zinc-blende and wurtzite GaAs quantum dots in nanowires studied using hydrostatic pressure

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