Microscopy of defects in semiconductors

Massabuau, Fabien; Bruckbauer, Jochen; Trager-Cowan, C.; Oliver, Rachel A.

doi:10.1049/pbcs045e_ch8

Cited by 4 publications

(2 citation statements)

References 131 publications

(215 reference statements)

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“…Figure 4(g) and 4(h) are taken in the g = 0002 and g = 112 ̅ 0 conditions respectively (as far as was possible given the issues with lamella bending described above). Within the limitations of the analysis imposed by the lamella bending, the fact that some of the dislocations running vertically up the boundary are out of contrast in the g = 112 ̅ 0 condition suggests that they are predominately c-Dislocations at coalescence boundaries in heteroepitaxial GaN/sapphire studied after the epitaxial layer has completely coalesced 12 type (b = 0001, therefore g.b = 0) 25 . There may be some vertical features in contrast in both the g = 0002 and g = 112 ̅ 0 image which would imply the presence of one or more (a+c)-type dislocations.…”

Section: Results and Analysismentioning

confidence: 99%

Dislocations at coalescence boundaries in heteroepitaxial GaN/sapphire studied after the epitaxial layer has completely coalesced

et al. 2021

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Section: Results and Analysismentioning

confidence: 99%

Dislocations at coalescence boundaries in heteroepitaxial GaN/sapphire studied after the epitaxial layer has completely coalesced

et al. 2021

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“…For example, dislocations can act as charged line defects attracting minority carriers, which then recombine non-radiatively at the defect [16]. To visualise and investigate the lateral distribution of these extended defects highly spatially-resolved imaging techniques, such as cathodoluminescence (CL), can be employed, where the defects appear as dark features [17]. CL imaging is a powerful and established tool to rapidly and non-destructively investigate the luminescence properties of light-emitting materials providing information on defects, composition, doping and strain [18].…”

Section: Introductionmentioning

confidence: 99%

Influence of micro-patterning of the growth template on defect reduction and optical properties of non-polar (112ˉ0) GaN

Bruckbauer

Gong

Jiu

et al. 2020

J. Phys. D: Appl. Phys.

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We investigate the influence of different types of template micro-patterning on defect reduction and optical properties of non-polar GaN using detailed luminescence studies. Non-polar ( 11 2 ˉ 0 ) (or a-plane) GaN exhibits a range of different extended defects compared with its more commonly used c-plane counterpart. In order to reduce the number of defects and investigate their impact on luminescence uniformity, non-polar GaN was overgrown on four different GaN microstructures. The micro-patterned structures consist of a regular microrod array; a microrod array where the −c-side of the microrods has been etched to suppress defect generation; etched periodic stripes and finally a subsequent combination of etched stripes and etched microrods (double overgrowth). Overall the presence of extended defects, namely threading dislocations and stacking faults (SFs) is greatly reduced for the two samples containing stripes compared with the two microrod samples. This is evidenced by more uniform emission and reduction in dark regions of non-radiative recombination in room temperature cathodoluminescence imaging as well as a reduction of the SF emission line in low temperature photoluminescence. The observed energy shifts of the GaN near band edge emission are related to anisotropic strain relaxation occurring during the overgrowth on these microstructures. A combination of stripes and microrods is a promising approach for defect reduction and emission uniformity in non-polar GaN for applications in light-emitting devices as well as power electronics.

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Pair suppression caused by mosaic-twist defects in superconducting Sr2RuO4 thin-films prepared using pulsed laser deposition

et al. 2020

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Sr 2 RuO 4 (SRO 214) is a prototypical unconventional superconductor. However, since the discovery of its superconductivity a quarter of a century ago, the symmetry of the bulk and surface superconducting states in single crystal SRO 214 remains controversial. Solving this problem is massively impeded by the fact that superconducting SRO 214 is extremely challenging to achieve in thin-films as structural defects and impurities sensitively annihilate superconductivity. Here we report a protocol for the reliable growth of superconducting SRO 214 thin-films by pulsed laser deposition and identify universal materials properties that are destructive to the superconducting state. We demonstrate that careful control of the starting material is essential in order to achieve superconductivity and use a single crystal target of Sr 3 Ru 2 O 7 (SRO 327). By systematically varying the SRO 214 film thickness, we identify mosaic twist as the key in-plane defect that suppresses superconductivity. The results are central to the development of unconventional superconductivity.

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Microscopy of defects in semiconductors

Cited by 4 publications

References 131 publications

Dislocations at coalescence boundaries in heteroepitaxial GaN/sapphire studied after the epitaxial layer has completely coalesced

Dislocations at coalescence boundaries in heteroepitaxial GaN/sapphire studied after the epitaxial layer has completely coalesced

Influence of micro-patterning of the growth template on defect reduction and optical properties of non-polar (112ˉ0) GaN

Pair suppression caused by mosaic-twist defects in superconducting Sr2RuO4 thin-films prepared using pulsed laser deposition

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