Probing Exciton Diffusion in Semiconductors Using Semiconductor‐Nanorod Quantum Structures

Yoo, Jinkyoung; Yi, Gyu‐Chul; Dang, Le Si

doi:10.1002/smll.200701293

Cited by 27 publications

(30 citation statements)

References 28 publications

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“…An electron beam accelerated at 10 kV voltage was used to achieve the optimum spatial resolution with the best signal-to-noise ratio, which results in the effective interaction region of electron beam in ZnO being ~100 nm (with 90% power in this interaction volume, as supported by Monte Carlo simulation17). As the exciton diffusion length in ZnO at low temperatures is ~100 nm18, the exciton emission peaks can clearly reveal the evolution of the band structure with strain by using scan step of ~100 nm.…”

Section: Resultsmentioning

confidence: 99%

Strain induced exciton fine-structure splitting and shift in bent ZnO microwires

Liao

et al. 2012

Sci Rep

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Lattice strain is a useful and economic way to tune the device performance and is commonly present in nanostructures. Here, we investigated for the first time the exciton spectra evolution in bent ZnO microwires along the radial direction via high spatial/energy resolution cathodeluminescence spectroscopy at 5.5 K. Our experiments show that the exciton peak splits into multi fine peaks towards the compressive part while retains one peak in the tensile part and the emission peak displays a continuous blue-shift from tensile to compressive edges. In combination with first-principles calculations, we show that the observed NBE emission splitting is due to the valence band splitting and the absence of peak splitting in the tensile part maybe due to the highly localized holes in the A band and the carrier density distribution across the microwire. Our studies may pave the way to design nanophotonic and electronic devices using bent ZnO nanowires.

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Section: Resultsmentioning

confidence: 99%

Strain induced exciton fine-structure splitting and shift in bent ZnO microwires

Liao

et al. 2012

Sci Rep

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“…The line-scanning step size was set at 200 nm considering the typical exciton diffusion length is about 200 nm in ZnO at this temperature. 40 Time-Resolved CL Measurement. The experimental setup for the time-resolved CL (TRCL) is composed of three blocks: the excitation block, the Attolight system for quantitative cathodoluminescence, and the detection block.…”

Section: Methodsmentioning

confidence: 99%

Exciton Drift in Semiconductors under Uniform Strain Gradients: Application to Bent ZnO Microwires

Jacopin

Shahmohammadi

et al. 2014

ACS Nano

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Optimizing the electronic structures and carrier dynamics in semiconductors at atomic scale is an essential issue for innovative device applications. Besides the traditional chemical doping and the use of homo/heterostructures, elastic strain has been proposed as a promising possibility. Here, we report on the direct observation of the dynamics of exciton transport in a ZnO microwire under pure elastic bending deformation, by using cathodoluminescence with high temporal, spatial, and energy resolutions. We demonstrate that excitons can be effectively drifted by the strain gradient in inhomogeneous strain fields. Our observations are well reproduced by a drift-diffusion model taking into account the strain gradient and allow us to deduce an exciton mobility of 1400 ( 100 cm 2 /(eV s) in the ZnO wire. These results propose a way to tune the exciton dynamics in semiconductors and imply the possible role of strain gradient in optoelectronic and sensing nano/microdevices.

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“…Without of specific statement, all the cross‐sectional measurement is produced by line‐scanning CL along the direction of r from the compressive to the tensile edge at a constant scan step of Δ r ∼ 60 nm. The sampled area for CL excitation is about 110 nm 17. An optimal setting is chosen (voltage of 9 keV and spot size of 4, an equipment setting) to achieve the optimum spatial resolution with high signal‐to‐noise ratio 18.…”

Section: Methodsmentioning

confidence: 99%

“…The ZnO microwires used in the present study were synthesized via vapor phase deposition method,10, 16 growing along the [0001] zone axis with hexagonal cross‐section, with diameters ranging from 0.3 to 2.5 μm, much larger than the exciton diffusion length in ZnO crystal (∼100 nm) 17. After dispersion in ethanol, the ZnO microwires were transferred onto Si substrates with 500 nm SiO 2 layer.…”

Section: The Fitting Coefficients β and α For All The Samples Note Tmentioning

confidence: 99%

Strain‐Gradient Effect on Energy Bands in Bent ZnO Microwires

et al. 2012

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The table of contents image illustrates the strain-gradient effect on the optical-electronic properties in a bent ZnO microwire, with a much stronger red-shift on the outer tensile side than a blue-shift on the inner compressive side. The low temperature cathodoluminescence cross-sectional scanning spectra on the strain-neutral middle-plane are highlighted by thicker black lines, which clearly shows a strain-gradient induced red-shift.

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Probing Exciton Diffusion in Semiconductors Using Semiconductor‐Nanorod Quantum Structures

Cited by 27 publications

References 28 publications

Strain induced exciton fine-structure splitting and shift in bent ZnO microwires

Strain induced exciton fine-structure splitting and shift in bent ZnO microwires

Exciton Drift in Semiconductors under Uniform Strain Gradients: Application to Bent ZnO Microwires

Strain‐Gradient Effect on Energy Bands in Bent ZnO Microwires

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