Transmission electron microscopy<b><i>in situ</i></b>investigation of dislocation behaviour in semiconductors and the influence of electronic excitation

Lavagne, S.; Levade, C.; Vanderschaeve, G.

doi:10.1080/14786430600750038

Cited by 4 publications

(3 citation statements)

References 29 publications

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“…When dealing with III-V-V materials the exact composition may influence dynamics, and to illustrate how much this can affect dynamics it was seen that defect velocity in GaP was 100 times that in GaAs [173]. Interaction of an electron beam is also known to influence defect dynamics [174][175][176].…”

Section: Mechanisms Of Defect Motionmentioning

confidence: 99%

“…In addition to uncertainties about NW shape there are several complicating factors that make quantitative study difficult. Factors include the different core structure of up-and down-steps; the variation of stacking fault energy with temperature [238]; pinning by impurity segregation [166,170,171]; varying composition in a core-shell structure; changes to the NW surface during heating [172]; and the effect of the electron beam [174][175][176]. In the absence of this information, it can only be said that these measurements give an upper bound to the activation energy of approximately 2 eV.…”

Section: Movement Stopped By Interactionsmentioning

confidence: 99%

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Defects in Self-Catalysed III-V Nanowires

Gott¹

2022

Springer Theses

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Semiconductor nanowires are poised to be a candidate for next-generation technology with superior performance and a high integration ability. They have unique physical properties that are enabled by their nano-scale form-factor. Nanowires are commonly described as being defect-free due to their ability to expel mobile defects with long-range strain fields. The droplet consumption step in self-catalysed III-V nanowires can produce material with a high density of line defects, often with null Burgers vector, i.e., no long-range strain field. The presence of such defects can diminish device performance and make them unreliable.This thesis presents an extensive study made into defects present in semiconductor nanowires. Defect structures are analysed from atomic resolution electron microscope images, and observations show that the nanowire microstructure is very different from bulk material. Nanowires can contain line defects that (a) are trapped by locks or other defects, (b) arranged as dipoles or groups with a zero total Burgers vector, or (c) have a zero Burgers vector. The most common defect is the three-monolayer high twin facet with a zero Burgers vector. Cathodoluminescence experiments reveal optical emission is quenched in defective regions, showing that they act as strong non-radiative recombination centers.Stability of defects is tested by in-situ electron microscopy to analyse defect behaviour in GaAsP nanowires using short annealing cycles. Movement of null Burgers vector defects appears to be consistent with the thermally activated singleor double-kink mechanisms of dislocation glide, with velocities that do not exceed 1 nm s −1 . Motion of null Burgers vector defects is found to depend on their size, position, and surrounding environment and sets an upper limit to activation energy around 2 eV. The majority of defects (>70%) are removed by post-growth annealing for several seconds at temperatures in excess of 640 °C, while the remaining defects do not move and are thermodynamically stable in the nanowire.Finally, axial heterostructures in GaAsP nanowires with GaAs quantum dots are examined and a selection of theoretical models are tested to see how well they fit experimental interfaces. Of the physical models tested, a model recently developed by Dubrovskii was found to best fit experimental data. Interface sharpness and size of quantum dots were measured for different nanowire radii and both showed no obvious trend. These results are explained by the low group V concentration and solubility in the catalyst, and length distribution of the nanowires respectively. xv

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Section: Mechanisms Of Defect Motionmentioning

confidence: 99%

Section: Movement Stopped By Interactionsmentioning

confidence: 99%

Defects in Self-Catalysed III-V Nanowires

Gott¹

2022

Springer Theses

View full text Add to dashboard Cite

show abstract

“…In addition to uncertainties about NW shape there are a formidable number of complicating factors that make quantitative study difficult. These include the different core structure of up- and down-steps; the variation of stacking fault energy with temperature; pinning by impurity segregation; ,, varying composition in a core–shell structure; changes to the NW surface during heating; and indeed the effect of the electron beam. − In the absence of this information, one can only say that these measurements only give an upper bound to the activation energy of ∼2 eV.…”

mentioning

confidence: 99%