Exciton dynamics in a novel high-yield GaInP quantum-wire array

Dua, P.; Cooper, Steve; Chen, A. C.; Cheng, K. Y.

doi:10.1063/1.117147

Cited by 10 publications

(3 citation statements)

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“…The polarization degree we find at the absorption edge (1010 nm) is of 3.5%, quite low compared with other QWR structures (>80%), 18 suggesting that the lateral confinement is relatively weak even at the ground state and the QWR character of these nanostructures is not strong. The polarization degree increases at longer wavelengths and goes down to zero at the shorter ones, consistent with more localised ground states in QWRs of different sizes and the presence of QW-like excited energy levels in the nanostructures.…”

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confidence: 86%

InGaAs/GaAsP strain balanced multi-quantum wires grown on misoriented GaAs substrates for high efficiency solar cells

Alonso-Álvarez

Thomas

Führer

et al. 2014

Applied Physics Letters

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Quantum wires (QWRs) form naturally when growing strain balanced InGaAs/GaAsP multi-quantum wells (MQW) on GaAs [100] 6° misoriented substrates under the usual growth conditions. The presence of wires instead of wells could have several unexpected consequences for the performance of the MQW solar cells, both positive and negative, that need to be assessed to achieve high conversion efficiencies. In this letter, we study QWR properties from the point of view of their performance as solar cells by means of transmission electron microscopy, time resolved photoluminescence and external quantum efficiency (EQE) using polarised light. We find that these QWRs have longer lifetimes than nominally identical QWs grown on exact [100] GaAs substrates, of up to 1 μs, at any level of illumination. We attribute this effect to an asymmetric carrier escape from the nanostructures leading to a strong 1D-photo-charging, keeping electrons confined along the wire and holes in the barriers. In principle, these extended lifetimes could be exploited to enhance carrier collection and reduce dark current losses. Light absorption by these QWRs is 1.6 times weaker than QWs, as revealed by EQE measurements, which emphasises the need for more layers of nanostructures or the use light trapping techniques. Contrary to what we expected, QWR show very low absorption anisotropy, only 3.5%, which was the main drawback a priori of this nanostructure. We attribute this to a reduced lateral confinement inside the wires. These results encourage further study and optimization of QWRs for high efficiency solar cells.

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confidence: 86%

InGaAs/GaAsP strain balanced multi-quantum wires grown on misoriented GaAs substrates for high efficiency solar cells

Alonso-Álvarez

Thomas

Führer

et al. 2014

Applied Physics Letters

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“…3,4 TEM measurements confirm the presence of wire regions in these structures, but fail to provide any information on either the extent or profile of the composition modulation. Since this composition modulation is the result of a self-ordering process, one does not a priori know the shape of the modulation profile.…”

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confidence: 86%

A novel tool for mapping composition distributions in semiconductor microstructures—application to InxGa1−xP quantum wires

Dua

Cooper

Cheng

1998

Applied Physics Letters

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Articles you may be interested inEffect of elastic strain redistribution on electronic band structures of compressively strained GaInAsP/InP membrane quantum wires Design of composite InAsP/InGaAs quantum wells for a 1.55 μm polarization independent semiconductor optical amplifier Appl.A technique is described which employs resonant Raman scattering for nondestructive, quantitative analysis of alloy composition distributions and their volume fractions in semiconductor microstructures. Use of this technique is demonstrated via application to extract the wire and barrier region compositions and the shape of the composition modulation profile of narrow (ϳ150 Å) In x Ga 1Ϫx P multiquantum wire array grown via a strain-induced laterally ordered process.

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“…9, where dot and dash lines represent biexponential fits to the data. 23 The initial decay time constant is 1.6 ns for P 1 and 1.8 ns for P 2 . The faster decay rate for P 1 and the reversal of P 1 and P 2 intensities indicate that channels for the diffusive transport of carriers between the P 1 and P 2 levels ͑QWR regions 4 and 1͒ exist.…”

Section: Time-delay CL Measurements Of the Carrier Relaxation Reementioning

confidence: 99%

Spatial variations in luminescence and carrier relaxation in molecular beam epitaxial grown (InP)2/(GaP)2 quantum wires

Tang¹

1997

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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Phase separation in III–V semiconductors has led to a unique method for fabricating quantum wires via a strain induced lateral ordering process. Quantum wire (QWR) arrays were formed during the gas source molecular beam epitaxial (MBE) growth of (InP)2/(GaP)2 bilayer superlattices (BSLs) and were studied by time-resolved and linearly polarized cathodoluminescence. Nonlinear optical properties, such as phase-space filling effects, were observed to be indicative of the QWR nature of the samples. Samples prepared by gas source MBE were found to have a greater uniformity, smaller QWRs, and higher optical quality in comparison to those obtained by metal–organic chemical vapor deposition. Misfit dislocations also formed in one of the BSL samples, indicating a partial strain relaxation at the GaAs/InGaP and BSL/InGaP interfaces. The carrier relaxation, transport, and collection in the QWRs were studied with time-resolved cathodoluminescence.

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Exciton dynamics in a novel high-yield GaInP quantum-wire array

Cited by 10 publications

References 0 publications

InGaAs/GaAsP strain balanced multi-quantum wires grown on misoriented GaAs substrates for high efficiency solar cells

InGaAs/GaAsP strain balanced multi-quantum wires grown on misoriented GaAs substrates for high efficiency solar cells

A novel tool for mapping composition distributions in semiconductor microstructures—application to InxGa1−xP quantum wires

Spatial variations in luminescence and carrier relaxation in molecular beam epitaxial grown (InP)2/(GaP)2 quantum wires

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