Nanocathodoluminescence Reveals Mitigation of the Stark Shift in InGaN Quantum Wells by Si Doping

Griffiths, James T.; Zhang, Siyuan; Rouet‐Leduc, Bertrand; Fu, Wai Yuen; Bao, An; Zhu, Dandan; Wallis, D. J.; Howkins, Ashley; Boyd, Ian W.; Stowe, David; Kappers, Menno J.; Humphreys, C. J.; Oliver, Rachel A.

doi:10.1021/acs.nanolett.5b03531

Cited by 36 publications

(31 citation statements)

References 36 publications

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“…Recently, by performing CL in a scanning transmission electron microscope (STEM) it has been possible to study nanoscale optical properties down to just a few nanometres 17,18 and reveal simultaneously the structural and chemical properties, an approach that is commonly referred to as nano-cathodoluminescence (nano-CL). This method has already shown great success in the characterisation of pure GaN nanocolumns 19 , InGaN nanodisk-rod structures 20 , and recently variations in the emission energy along the sidewalls of InGaN core-shell nanorods 21 .…”

mentioning

confidence: 99%

Structural impact on the nanoscale optical properties of InGaN core-shell nanorods

Griffiths¹,

Ren²,

Coulon

et al. 2017

Applied Physics Letters

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III-nitride core-shell nanorods are promising for the development of high efficiency light emitting diodes and novel optical devices. We reveal the nanoscale optical and structural properties of core-shell InGaN nanorods formed by combined top-down etching and regrowth to achieve non-polar sidewalls with a low density of extended defects. While the luminescence is uniform along the non-polar {1–100} sidewalls, nano-cathodoluminescence shows a sharp reduction in the luminescent intensity at the intersection of the non-polar {1–100} facets. The reduction in the luminescent intensity is accompanied by a reduction in the emission energy localised at the apex of the corners. Correlative compositional analysis reveals an increasing indium content towards the corner except at the apex itself. We propose that the observed variations in the structure and chemistry are responsible for the changes in the optical properties at the corners of the nanorods. The insights revealed by nano-cathodoluminescence will aid in the future development of higher efficiency core-shell nanorods

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mentioning

confidence: 99%

Structural impact on the nanoscale optical properties of InGaN core-shell nanorods

Griffiths¹,

Ren²,

Coulon

et al. 2017

Applied Physics Letters

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“…In the TEM sphere, we are increasingly seeing integration of techniques for the characterisation of (opto)electronic properties of materials directly into the electron microscope. One exciting example of this is the application of CL in the TEM, where the limited interaction volumes attainable due to the use of thin film samples aids the achievement of excellent resolution [144]. Similarly, SEM-based techniques are becoming ever more sophisticated, with CL experiments in the SEM being extended to allow time-resolved as well as time-integrated experiments [145].…”

Section: Discussionmentioning

confidence: 99%

Microscopy of defects in semiconductors

Massabuau

Bruckbauer

Trager-Cowan

et al. 2019

Characterisation and Control of Defects in Semiconductors

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“…We envision this type of dual-beam based technique for the extraction and analysis of features on this scale could be extended with the use of various TEM-based analysis methods such as nanocathodoluminescence (nanoCL) [72] or electron tomography [73] for the investigation of specific nano-scale features in devices beyond microdisk cavities, such as photonic crystal cavities [9,74], providing a promising platform for device analysis and optimisation.…”

Section: Evidence For Dislocation Induced Whiskers In Microdisksmentioning

confidence: 99%

Defects in III-nitride microdisk cavities

Ren¹,

Puchtler²,

Zhu³

et al. 2017

Semicond. Sci. Technol.

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Nitride microcavities offer an exceptional platform for the investigation of light-matter interactions as well as the development of devices such as high efficiency light emitting diodes (LEDs) and lowthreshold nanolasers. Microdisk geometries in particular are attractive for low-threshold lasing applications due to their ability to support high finesse whispering gallery modes (WGMs) and small modal volumes. In this article we review the effect of defects on the properties of nitride microdisk cavities fabricated using photoelectrochemical (PEC) etching of an InGaN sacrificial superlattice (SSL). Threading dislocations originating from either the original GaN pseudosubstrate are shown to hinder the undercutting of microdisk cavities during the photoelectric chemical (PEC) etching process resulting in whiskers of unetched material on the underside of microdisks. The unetched whiskers provide a pathway for light to escape, reducing microdisk Q-factor if located in the region occupied by the WGMs. Additionally, dislocations can affect the spectral stability of quantum dot emitters, thus hindering their effective integration in microdisk cavities. Though dislocations are clearly undesirable, the limiting factor on nitride microdisk Q-factor is expected to be internal absorption, indicating that the further optimisation of nitride microdisk cavities must incorporate both the elimination of dislocations and careful tailoring of the active region emission wavelength and background doping levels.

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Nanocathodoluminescence Reveals Mitigation of the Stark Shift in InGaN Quantum Wells by Si Doping

Cited by 36 publications

References 36 publications

Structural impact on the nanoscale optical properties of InGaN core-shell nanorods

Structural impact on the nanoscale optical properties of InGaN core-shell nanorods

Microscopy of defects in semiconductors

Defects in III-nitride microdisk cavities

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