Strained GaAs/InGaAs Core-Shell Nanowires for Photovoltaic Applications

Moratis, K.; Tan, Siew Li; Germanis, S.; Katsidis, C. C.; Androulidaki, M.; Tsagaraki, K.; Hatzopoulos, Z.; Donatini, Fabrice; Cibert, J.; Niquet, Yann-Michel; Mariette, H.; Pelekanos, N.T.

doi:10.1186/s11671-016-1384-y

Cited by 21 publications

(27 citation statements)

References 28 publications

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“…For example, NWs can absorb visible light more efficiently than planar structures due to the similarity between their size and the corresponding wavelength [5,6]. In addition, the formation of core-shell structures can further improve the performance of solar cells [7][8][9][10][11] and offers alternative opportunities for light emitting diodes [12][13][14][15][16]. In particular, due to their small diameter and high surface-to-volume ratio, core-shell NW heterostructures can be formed of highly lattice-mismatched materials allowing strain accommodation more efficiently than in the planar counterparts [17,18].…”

Section: Introductionmentioning

confidence: 99%

“…The NW density was extracted from SEM images, and the core-shell configuration, nominal dimensions, and nominal In content of the (In,Ga)As shell mentioned in the first four rows were deduced from MBE growth parameters. The In concentration x, thickness t, and the out-of-plane as well as in-plane elastic strain values of the (In,Ga)As shell listed in the last four rows were determined from XRD measurements along the [111] and [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] direction as described in the text. However, for sample 3 the In content had to be deduced from the parasitic growth on the substrate between the NWs.…”

Section: Introductionmentioning

confidence: 99%

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Determination of indium content of GaAs/(In,Ga)As/(GaAs) core-shell(-shell) nanowires by x-ray diffraction and nano x-ray fluorescence

Hassan

Lewis

Küpers

et al. 2018

Phys. Rev. Materials

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We present two complementary approaches to investigate the In content in GaAs/(In,Ga)As/(GaAs) core-shell-(shell) nanowire (NW) heterostructures using synchrotron radiation. The key advantage of our methodology is that NWs are characterized in their as-grown configuration, i.e., perpendicularly standing on a substrate. First, we determine the mean In content of the (In,Ga)As shell by high-resolution x-ray diffraction (XRD) from NW ensembles. In particular, we disentangle the influence of In content and shell thickness on XRD by measuring and analyzing two reflections with diffraction vector parallel and perpendicular to the growth axis, respectively. Second, we study the In distribution within individual NWs by nano x-ray fluorescence. Both the NW (111) basal plane, that is parallel to the surface of the substrate, and the {10-1} sidewall plane were scanned with an incident nanobeam of 50 nm width. We investigate three samples with different nominal In content of the (In,Ga)As shell. In all samples, the average In content of the shell determined by XRD is in good agreement with the nominal value. For a nominal In content of 15%, the In distribution is fairly uniform between all six sidewall facets. In contrast, in NWs with nominally 25% In content, different sidewall facets of the same NW exhibit different In contents. This effect is attributed to shadowing during growth by molecular beam epitaxy. At the same time, along the NW axis the In distribution is still fairly homogeneous. In NWs with 60% nominal In content and no outer GaAs shell, the In content varies significantly both between different sidewall facets and along the NW axis. This fluctuation is explained by the formation of (In,Ga)As mounds that grow simultaneously with a thinner (In,Ga)As shell. The methodology presented here may be applied also to other core-shell NWs with a ternary shell and paves the way to correlating NW structure with functional properties that depend on the as-grown configuration of the NWs.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Determination of indium content of GaAs/(In,Ga)As/(GaAs) core-shell(-shell) nanowires by x-ray diffraction and nano x-ray fluorescence

Hassan

Lewis

Küpers

et al. 2018

Phys. Rev. Materials

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“…Ternary group-IIIarsenide core-shell QWs have shown great promise in NW-based emitters/lasers [1][2][3][4] and detectors/solar cells. [5][6][7][8] Notably, (In,Ga)Asbased emitters have the potential to operate at the so-called telecommunication band; 9 such a combination of nanoscale emitters with Si waveguides promises to revolutionize the speed and energy efficiency of on-chip information transfer. 10 Recently, key steps towards nanophotonic on-chip integration of such devices on Si were demonstrated.…”

mentioning

confidence: 99%

Correlated Nanoscale Analysis of the Emission from Wurtzite versus Zincblende (In,Ga)As/GaAs Nanowire Core–Shell Quantum Wells

et al. 2019

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“…The III–V semiconductor systems offer many advantages such as high electron mobilities, a wide range of direct bandgaps, and the ability to form alloy compounds. Thus, they contribute as active elements in devices, such as laser diodes (LDs) for optical communications, light emitting diodes (LEDs), sensors, and photovoltaics …”

Section: Introductionmentioning

confidence: 99%

3‐D Strain Fields in Low‐Dimensional III–V Semiconductors: A Combined Finite Elements and HRTEM Approach

Florini

Dimitrakopulos

Kioseoglou

et al. 2017

Physica Status Solidi (a)

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A versatile route toward the study of strain fields of low-dimensional III-V semiconductor nanostructures is presented, by combining quantitative highresolution transmission electron microscopy (HRTEM) observations with the finite elements method (FEM). FEM facilitates a fast and straightforward threedimensional (3-D) analysis of elastic properties for various growth orientations and compositional profiles down to the nanoscale. FEM calculations are employed to simulate elastic stress-strain fields of III-V cubic heterostructures comprising InAs surface and buried quantum dots (QDs) grown on GaAs(211)B substrates, and (111)-oriented GaAs/Al x Ga (1Àx) As core-shell nanowires (NWs) on Si. The results are compared with experimental strain maps obtained from HRTEM images by geometric phase analysis (GPA), as well as with molecular dynamics (MD) atomistic simulations. In the former, the compositional grading along the growth axis was considered, and, in the latter, elastic fields were calculated as a function of the shell's chemical composition and shell-to-NW diameter ratios. The agreement between FEM calculations with experimental and theoretical results implies that the plane-stress state can adequately describe the encountered elastic fields. Most importantly, through the determined stress-strain state, strain fields can be translated into 3-D maps of chemical composition in the nanostructures, extracted from 2-D experimental projections.

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Strained GaAs/InGaAs Core-Shell Nanowires for Photovoltaic Applications

Cited by 21 publications

References 28 publications

Determination of indium content of GaAs/(In,Ga)As/(GaAs) core-shell(-shell) nanowires by x-ray diffraction and nano x-ray fluorescence

Determination of indium content of GaAs/(In,Ga)As/(GaAs) core-shell(-shell) nanowires by x-ray diffraction and nano x-ray fluorescence

Correlated Nanoscale Analysis of the Emission from Wurtzite versus Zincblende (In,Ga)As/GaAs Nanowire Core–Shell Quantum Wells

3‐D Strain Fields in Low‐Dimensional III–V Semiconductors: A Combined Finite Elements and HRTEM Approach

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