Europium Doped Silicon Oxide Thin Films Using an Integrated PECVD and Sputtering System
Bibliographic record
Abstract
Over the last decades, silicon-based materials have exhibited outstanding electronic properties and been used in photovoltaic and electrical devices such as transistors [1]. However, due to their indirect band gap nature and poor light emitting properties, they are not satisfying candidates when it comes to photonics. One way through which this poor performance is sorted out is doping of rare earth (RE) elements into the silicon nanostructure thin film to enhance the light emission. The reason for the use of RE elements in silicon-based materials is the fact that they showed well-defined emission peaks and 4f electron shielding making them independence of the host matrix [2]. In this study, luminescence properties of Europium (Eu) doped oxygen rich silicon oxide (ORSO) materials using two fabrication techniques are discussed as well as controlling of the Eu concentration, argon partial pressure and sputtering power. In addition, the effect of different annealing atmospheres is observed as here pure nitrogen (N2) and forming gas (N2+5% H2) are tested at a variety of deposition temperatures ranging between 300 °C and 1350 °C. In particular, samples subjected to the higher annealing temperatures of 1200 °C and 1350 °C behave differently in comparison with lower annealing temperatures where their structural and photoluminescence (PL) properties are investigated in more details. The introducing of Eu into ORSO host matrix was performed by two different deposition methods with the first one being the conventional method of metal organic powders where RE elements are introduced using electron cyclotron resonance plasma enhanced chemical vapor deposition (ECR-PECVD) system. The second method involves the use of a novel and custom-made integration of ECR-PECVD and magnetron sputtering [3]. The investigation of a variation of optical and structural properties of the samples made with similar deposition parameters using these two different techniques resulted in insignificant light emission of the ones fabricated with metal organic precursor and remarkable emission of the samples produced using the integrated ECR-PECVD and sputtering method. Variable angle spectroscopic ellipsometry (VASE) measurements are carried to comprehend the refractive index and thin films thicknesses, and their dependence on the deposition parameters such as the sputtering power. Rutherford backscattering spectrometry (RBS) measurements provide the film composition and verify a good control of the Eu concentration using the second deposition method (integrated ECR-PECVD and sputtering). X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM) confirm the formation of nanostructures in the Eu-ORSO thin films following post-deposition annealing beyond 1200 °C. The PL studies are performed to study the light emission properties of Eu-ORSO thin films and the changes introduced by the hydrogen passivation. Figure 1 shows the influence of hydrogen passivation on one of the Eu-ORSO thin films containing 0.1 ± 0.01 at. % of Eu. The sample is annealed at 1200 °C and 1350 °C using N2 and N2+H2 atmospheres for 1 hour in the quartz tube furnace. The hydrogen passivation enhances the PL emission by one order of magnitude possibly due to the passivation of the defects and dangling bonds. References: 1-Priolo, F., Gregorkiewicz, T., Galli, M., & Krauss, T. F. (2014). Silicon nanostructures for photonics and photovoltaics. Nature Nanotechnology, 9(1), 19–32. https://doi.org/10.1038/nnano.2013.271 2- Kenyon, A. J. (2002). Recent developments in rare-earth doped materials for optoelectronics. In Progress in Quantum Electronics (Vol. 26). https://doi.org/10.1016/S0079-6727(02)00014-9 3- Miller, J. W., Khatami, Z., Wojcik, J., Bradley, J. D. B., & Mascher, P. (2018). Integrated ECR-PECVD and magnetron sputtering system for rare-earth-doped Si-based materials. Surface and Coatings Technology, 336, 99–105. https://doi.org/10.1016/j.surfcoat.2017.08.051 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 | 0.001 |
| 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 | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".