Single Photon Emission Characteristics of Selective Area Grown InGaN/GaN Dot-in-Nanowires on N-Face GaN Substrate
Bibliographic record
Abstract
Single photon emitters (SPEs) and entangled photon pairs are critical enablers for various quantum applications, including quantum communication, computing, and sensing. Unlike conventional atoms/ions and defects-based SPEs, epitaxial, defects-free semiconductor dot-in-nanowires are promising to generate high-brightness, high-purity, indistinguishable single photons and entangled photon pairs on demand at high temperature. To this end, InGaN/GaN dot-in-nanowires are considered prospective for their tunability over a wide range of the electromagnetic spectrum [1, 2]. Conventionally these nanowires (NWs) are grown by metalorganic chemical vapor deposition (MOCVD) or molecular beam epitaxy (MBE) techniques on metal (Ga)-polar GaN or GaN-on-sapphire substrates. However N-face GaN surfaces are considered promising forthe growth of III-nitride nanowires for enhanced indium-incorporation, lower point defects, favorable piezoelectric field, reduced lateral growth, and enhanced verticality with nearly flat-top surfaces [3, 4]. In this work we investigate the prospect of realizing quantum emitters based on selective area grown InGaN/GaN dot-in-nanowires on N-face GaN substrates. The nanowires have been grown by plasma-assisted molecular beam epitaxy (PAMBE) on N-face side of single crystal GaN substrate having SiO2 masks atop, formed by e-beam lithography and reactive ion etching. NWs of different diameters (ranging from 10 nm - 200 nm) and areal density have been grown by changing the pattern design (lattice constant/spacing) and growth parameters (growth temperature, In/Ga beam equivalent pressure/molecular flux, N2 flow).The alloy composition of the InGaN/GaN active region is optimized for emission in the 450 nm-650 nm spectral range. Light output characteristics of the as-grown NWs were obtained by micro photoluminescence measurements. The sparsely grown NWs have been selectively excited using a high-precision piezo-stage (Attocube) and an objective lens (Zeiss) of high magnification and numerical aperture (NA=0.9). Preliminary results show the presence of multiple shoulder peaks, indicating the presence of excitonic, bi-excitonic and/or trionic states. Excitation (both off- and on-resonant) and temperature dependent measurements are currently underway to understand the nature of these emissions in the context of quantum emission. Time resolved and time-correlated measurements will be performed to investigate the lifetimes, spectral purity and temporal coherence of these emitters. The experimental characterization will ultimately provide insight into the prospect of harnessing single-photon emission from selective area grown N-polar InGaN/GaN nanowires, on N-face GaN substrates. References: [1] S. Deshpande et al., Nat. Commun. 4 (1), 1675 (2013) [2] L. Zhang, Appl. Phys. Lett. 108, 153102 (2016) [3] X. Liu et al., Photonics Res. 10(2), 587–593 (2022) [4] K. Khan et al., J. Cryst. Growth 611, 127181 (2023) Acknowledgement: This work was supported by the Natural Sciences and Engineering Research Council of Canada (NSERC) through Quantum Alliance Grant Programs Figure 1
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".