Axial EBIC oscillations at core/shell GaAs/Fe nanowire contacts

Yang, Mingze; Dvořák, Dalimil; Leistner, K.; Damm, Christine; Watkins, Simon P.; Kavanagh, K. L.

doi:10.1088/1361-6528/aae7fb

Cited by 5 publications

(6 citation statements)

References 27 publications

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“…depletion width or L). The 3 kV beam rather than 5 kV was used specifically to increase the lateral resolution while still fulfilling the low injection criterion [27]. This beam voltage also lowered the degree of back side collection, restricting analysis to charge collection kinetics at the front facets.…”

Section: Resultsmentioning

confidence: 99%

Geometric effects on carrier collection in core–shell nanowire p–n junctions

Yang¹,

Izadi-Darbandi²,

Watkins³

et al. 2021

Nano Futures

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We report electron-beam-induced current (EBIC) microscopy carried out on free-standing GaAs nanowire core–shell, p–n tunnel junctions. The carrier kinetics in both the n-type core and the p-type shell were determined by analyzing radial EBIC profiles as a function of beam energy. These profiles are highly sensitive to geometric effects such as facet width, shell and core thicknesses, and depletion widths. Combined with Monte Carlo simulations, they permitted measurement of the minority carrier diffusion lengths in the core and the shell, as well as the depletion widths as a function of radial direction. The relatively short minority carrier diffusion length in the core (50 nm), can be attributed to bulk point defects originating from low-temperature core growth (400 ∘C), or to interfacial recombination at traps at the p–n junction.

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Section: Resultsmentioning

confidence: 99%

Geometric effects on carrier collection in core–shell nanowire p–n junctions

Yang¹,

Izadi-Darbandi²,

Watkins³

et al. 2021

Nano Futures

Self Cite

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“…As shown in Figure 8d, a higher current is collected at the bottom of the wire and a lower current is collected at the top. Several factors could affect the axial collection properties of a core/shell wire, such as inhomogeneous properties of the core/shell junction along the axis, increased defect density on top and different core and shell resistance 31,53 . However, the radial analysis of the EBIC profile revealed a highly homogeneous junction while an increased defect density would have resulted in a sharper variation of the signal, as for bulk materials 54 .…”

Section: (C) Homogeneity Assessment By Ebic Mappingmentioning

confidence: 99%

Characterisation of Semiconductor Nanowires by Electron Beam Induced Microscopy and Cathodoluminescence

Tchernycheva

Jacopin

Piazza

2020

Fundamental Properties of Semiconductor Nanowires

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Nowadays the realization of market-competitive devices based on nanomaterials is a major challenge. Optimization of the device performance requires deep understanding of the physical phenomena at the nanoscale. In this context, electron beambased techniques become indispensable. Several instruments have been developed in the past decades to provide versatile diagnostic solutions for improving materials, designs and device fabrication. These characterization techniques applied to nanostructured semiconductors can help filling the gap between material science and engineering by bringing in light important physical parameters.In this Chapter, the family of electron beam-based techniques is briefly introduced. First, the electron beam/matter interaction is described both in physical and operational terms. In particular, different phenomena occurring when a flux of electron collides with a semiconductor material are discussed. Then, two main electron beam scanning techniques are discussed in the following sections: electron beam induced current microscopy and cathodoluminescence. After a short description of the fundamentals, for each technique a bibliographic review is presented to illustrate its applications to analyses of semiconductor nanowires.

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“…z>2L and R = L [12] where R is the electron range relationship determining the average radius of interacting volume (see equation (2) below). This equation has been used by many authors to determine the diffusion length of charge carriers for NW solar cells [16][17][18][19][20][21][22][23][24][25][26][27], however its validity can be open questioned. In the case of nanowires, because of their small radial dimension, the surface to the volume ratio is high, rendering surface effects not negligible.…”

Section: Introductionmentioning

confidence: 99%

Modeling of the electron beam induced current signal in nanowires with an axial p-n junction

Lahreche¹,

Babichev²,

Beggah³

et al. 2022

Nanotechnology

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A tridimensional mathematical model to calculate the electron beam induced current (EBIC) of an axial p-n nanowire junction is proposed. The effect of the electron beam and junction parameters on the distribution of charge carriers and on the collected EBIC current is reported. We demonstrate that the diffusion of charge carriers within the wire is strongly influenced by the electrical state of its lateral surface which is characterized by a parameter called surface recombination velocity (v r). When the surface recombination is weak (i.e. low v r value), the diffusion of charge carriers occurs in one dimension (1-D) along the wire axis, and, in this case, the use of bulk EBIC models to extract the diffusion length (L) of charge carriers is justified. However, when the surface effects are strong (i.e. high v r values), the diffusion happens in three dimensions (3-D). In this case, the EBIC profiles depend on v r value and two distinct cases can be defined. If the L is larger than the nanowire radius (r a), the EBIC profiles show a strong dependency with this parameter. This gives evidence that the recombination of generated carriers on the surface through v r is the dominant process. In this situation, a decrease of two orders of magnitude in the EBIC profiles computed with a high and a low v r value is observed in neutral regions of the junction. For the case of L smaller than r a the dependency of the EBIC profiles on the v r is weak, and the prevalent recombination mechanism is the bulk recombination process.

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Axial EBIC oscillations at core/shell GaAs/Fe nanowire contacts

Cited by 5 publications

References 27 publications

Geometric effects on carrier collection in core–shell nanowire p–n junctions

Geometric effects on carrier collection in core–shell nanowire p–n junctions

Characterisation of Semiconductor Nanowires by Electron Beam Induced Microscopy and Cathodoluminescence

Modeling of the electron beam induced current signal in nanowires with an axial p-n junction

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