Origin of radiative recombination and manifestations of localization effects in GaAs/GaNAs core/shell nanowires

Chen, Shula; Filippov, Stanislav; Ishikawa, Fumitaro; Chen, Weimin; Buyanova, Irina

doi:10.1063/1.4905090

Cited by 27 publications

(46 citation statements)

References 39 publications

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“…17,18 To improve the carrier lifetime, the suppression of the surface states by growing a shell layer of AlGaAs or GaAsP is of crucial importance. However, the opposite trend was recently reported 19 for GaNAs NWs, the room-temperature carrier lifetime of which was found to be improved. The reason could be the formation of Ga-N bonds at the GaAs surface, which causes the passivation of Ga dangling bonds.…”

mentioning

confidence: 53%

Self-catalyzed core-shell GaAs/GaNAs nanowires grown on patterned Si (111) by gas-source molecular beam epitaxy

Liu

Yao

Chen

et al. 2017

Applied Physics Letters

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We report structural studies on the epitaxial growth of GaAs/GaNAs core-shell nanowires (NWs) on patterned Si (111) substrates by self-catalyzed selective area growth using Gas-Source Molecular Beam Epitaxy. Epitaxial growth conditions were obtained using a combination of dry and time-sensitive wet etching of the SiO2 growth mask and native SiO2 layer, respectively. We found that higher growth temperatures resulted in a higher yield for the epitaxial growth of patterned self-catalyzed GaAs NWs on Si with an optimal temperature of 690 °C. The GaNAs shell growth at 500 °C was found to be conformal and maintained an epitaxial and dislocation-free interface with both the Si substrate and the GaAs nanowire. The micro-photoluminescence (μ-PL) measurement at 6 K revealed two bands peaking at 1.45 and 1.17 eV, which could be emission from the GaAs core and GaNAs shell. Transmission electron microscopy showed the zincblende crystal structure of GaAs and GaAs/GaNAs core-shell NWs with minimal twinning near the base of the GaAs nanowires and at the tips of the GaAs/GaNAs core/shell nanowires. This study illustrates the feasibility of the epitaxial growth of patterned GaAs with dilute nitride shells on Si substrates, which would have potential for Si-friendly intermediate band solar cells and telecom emitters.

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confidence: 53%

Self-catalyzed core-shell GaAs/GaNAs nanowires grown on patterned Si (111) by gas-source molecular beam epitaxy

Liu

Yao

Chen

et al. 2017

Applied Physics Letters

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“…31,47 Similar results have also been reported in GaAs/GaNAs core/shell NWs. 48 The observed large Stokes shift between the PL and PLE spectra provide further evidence that the low-temperature PL emission in the GaNAsP NWs entirely stems from the LE recombination.…”

Section: A Origin Of the Pl Emissionmentioning

confidence: 74%

Effects of Nitrogen Incorporation on Structural and Optical Properties of GaNAsP Nanowires

Jansson

Chen

et al. 2017

J. Phys. Chem. C

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In this work we carry out a comprehensive investigation of structural and optical effects in GaNAsP nanowires (NWs), which are novel materials promising for advanced photovoltaic applications. Despite a significant mismatch in electronegativity between N and As/P atoms, we show that incorporation of nitrogen does not degrade structural quality of the nanowires and the fabricated NW arrays have excellent compositional uniformity among individual wires. From temperature-dependent photoluminescence (PL) measurements, statistical fluctuations of the alloy composition are shown to lead to localization of photo-excited carriers at low temperatures but do not affect material properties at room temperature. According to time-resolved PL measurements, the room-temperature carrier lifetime increases in the GaNAsP NWs as compared with the GaAsP NWs, which indicates reduced non-radiative recombination. Moreover, in spite of the very low N content in the studied NWs (up to 0.16 %), their bandgap energy can be tuned by more than 100 meV. This is accompanied by about 30% reduction in the temperature dependence of the bandgap energy. The presented results demonstrate that alloying of GaAsP with nitrogen provides an additional means of design optimization, beneficial for, e.g., NW-based intermediate band solar cells that are highly dependent on the optimum bandgap structure.

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“…So the light emission enhancement observed in our experiment cannot be introduced by the chemical reactions reported in previous studies. 23,24 For determining the interaction between N 2 molecules and GaAs NWs, we calculated the electron localization function (ELF) of the N 2 @GaAs system under high pressure based on density functional theory (DFT). As shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

Enhancing the light emission of GaAs nanowires by pressure-modulated charge transfer

Wang

Yin

et al. 2020

Nanoscale Adv.

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Strong non-radiative surface recombination in GaAs nanowires heavily blocks their applications as nanoscale optoelectronic devices. Pressure can effectively affect the surface recombination behaviors through tuning interactions between the surface of nanomaterials and the medium environment. Here, we report the pressure-induced light emission enhancement in GaAs nanowires via in situ high pressure photoluminescence measurements with nitrogen as the pressure transmitting medium. In the pressure range from 0 to 2.2 GPa, the photoluminescence intensity dramatically increases with increasing pressure. Above 2.2 GPa, the band gap transition from direct to indirect results in a sudden decrease in the photoluminescence intensity. Photoluminescence enhancement in GaAs nanowires also shows the pressure-dependent reversibility. The pressure-enhanced charge transfer effect between nitrogen molecules and the GaAs nanowire surface has been revealed according to first-principles calculations, which results in the reduction of surface states and the light-emission enhancement in GaAs NWs. Our study can provide a potential route for optimizing nanoscale functional devices.

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Origin of radiative recombination and manifestations of localization effects in GaAs/GaNAs core/shell nanowires

Cited by 27 publications

References 39 publications

Self-catalyzed core-shell GaAs/GaNAs nanowires grown on patterned Si (111) by gas-source molecular beam epitaxy

Self-catalyzed core-shell GaAs/GaNAs nanowires grown on patterned Si (111) by gas-source molecular beam epitaxy

Effects of Nitrogen Incorporation on Structural and Optical Properties of GaNAsP Nanowires

Enhancing the light emission of GaAs nanowires by pressure-modulated charge transfer

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