Dissertation/ Thesis
Optical and electronic properties of colloidal CdSe nanoplatelets and related heterostructures ; Propriétés optiques et électroniques des nanoplaquettes colloidales de CdSe et des hétérostructures associées
| العنوان: | Optical and electronic properties of colloidal CdSe nanoplatelets and related heterostructures ; Propriétés optiques et électroniques des nanoplaquettes colloidales de CdSe et des hétérostructures associées |
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| المؤلفون: | Ngo, Huu Thoai |
| المساهمون: | Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 (IEMN), Centrale Lille-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)-JUNIA (JUNIA), Université catholique de Lille (UCL)-Université catholique de Lille (UCL), Physique - IEMN (PHYSIQUE - IEMN), Université catholique de Lille (UCL)-Université catholique de Lille (UCL)-Centrale Lille-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)-JUNIA (JUNIA), Université de Lille, Universiteit Gent (1817-.), Louis Biadala, Iwan Moreels, Gang Ji |
| المصدر: | https://theses.hal.science/tel-04876327 ; Micro and nanotechnologies/Microelectronics. Université de Lille; Universiteit Gent (1817-.), 2024. English. ⟨NNT : 2024ULILN025⟩. |
| بيانات النشر: | CCSD |
| سنة النشر: | 2024 |
| المجموعة: | Université Polytechnique Hauts-de-France: HAL |
| مصطلحات موضوعية: | Stm, Propriétés électroniques, Dimensionality, Hr-Tem, Electronic properties, Heteronanostructures, Dimensionnalité, Hétéronanostructures, Nanoplaquettes, Confinement quantique, [SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics |
| الوصف: | Advances in colloidal chemistry have enabled the synthesis of various colloidal nanocrystals (NCs) such as quantum dots (QDs), quantum rings (QRs), nanoplatelets (NPLs) and nanorods (NRs), characterised by quantum confinement effects. Among them, colloidal NPLs (e.g. CdSe, PbSe) stand out for their unique shape and scalable optoelectronic properties. However, colloidal NPLs contain numerous surface traps, caused by structural defects and incomplete ligand passivation, which greatly reduce the quantum efficiency of NPLs, thus affecting the performance of NPL-based optoelectronic devices. It is therefore necessary to understand the structural and electronic properties of NPLs at the individual scale.In this thesis, I studied the structural and electronic properties of CdSe NPLs using scanning tunneling microscopy (STM), which revealed the presence of atomic terraces on the truncated edges of the NPLs. Scanning tunneling spectroscopy (STS) was used to detect the energy positions of the electronic trap states in the band gap.The influence of trap states (surface dangling bonds) on the optical properties of NPLs was demonstrated by measurements of the magneto-optical properties of CdSe NPLs and CdSe/CdS core/crown NPLs. Interactions between the electron spin and those of the surface dangling bonds lead to a non-monotonic circular polarisation (DCP) in the magnetic field of the emission from CdSe NPLs. The progressive suppression of these interactions during the growth of CdS rings around the active CdSe core indicates that the active dangling bonds are located at the edges of the NPLs. This finding confirms the key role of surface DBs on the lateral facets in determining the magneto-optical effects in CdSe NPLs. I extended this thesis work to the study of ultrathin PbSe NPLs using the STM/STS technique, confirming the quantum confinement effects through the variation in thickness and lateral size, impacting their band gap and optoelectronic properties for telecommunications applications. ; Les progrès en chimie ... |
| نوع الوثيقة: | doctoral or postdoctoral thesis |
| اللغة: | English |
| Relation: | NNT: 2024ULILN025 |
| الاتاحة: | https://theses.hal.science/tel-04876327 https://theses.hal.science/tel-04876327v1/document https://theses.hal.science/tel-04876327v1/file/These_NGO_Huu_Thoai.pdf |
| Rights: | info:eu-repo/semantics/OpenAccess |
| رقم الانضمام: | edsbas.BE2B464D |
| قاعدة البيانات: | BASE |
| الوصف غير متاح. |