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Title: Structural and optical properties of size controlled Si nanocrystals in Si{sub 3}N{sub 4} matrix: The nature of photoluminescence peak shift

Superlattices of Si{sub 3}N{sub 4} and Si-rich silicon nitride thin layers with varying thickness were prepared by plasma enhanced chemical vapor deposition. After high temperature annealing, Si nanocrystals were formed in the former Si-rich nitride layers. The control of the Si quantum dots size via the SiN{sub x} layer thickness was confirmed by transmission electron microscopy. The size of the nanocrystals was well in agreement with the former thickness of the respective Si-rich silicon nitride layers. In addition X-ray diffraction evidenced that the Si quantum dots are crystalline whereas the Si{sub 3}N{sub 4} matrix remains amorphous even after annealing at 1200 °C. Despite the proven Si nanocrystals formation with controlled sizes, the photoluminescence was 2 orders of magnitude weaker than for Si nanocrystals in SiO{sub 2} matrix. Also, a systematic peak shift was not found. The SiN{sub x}/Si{sub 3}N{sub 4} superlattices showed photoluminescence peak positions in the range of 540–660 nm (2.3–1.9 eV), thus quite similar to the bulk Si{sub 3}N{sub 4} film having peak position at 577 nm (2.15 eV). These rather weak shifts and scattering around the position observed for stoichiometric Si{sub 3}N{sub 4} are not in agreement with quantum confinement theory. Therefore theoretical calculations coupled with the experimental results of different barriermore » thicknesses were performed. As a result the commonly observed photoluminescence red shift, which was previously often attributed to quantum-confinement effect for silicon nanocrystals, was well described by the interference effect of Si{sub 3}N{sub 4} surrounding matrix luminescence.« less
Authors:
; ; ;  [1] ;  [2] ;  [3] ; ;  [4] ;  [5] ;  [6] ; ; ; ;  [7] ;  [7] ;  [8] ;
  1. Faculty of Engineering, IMTEK, Albert-Ludwigs-University Freiburg, Georges-Köhler-Allee 103, 79110 Freiburg (Germany)
  2. Department of Electronic and Electrical Engineering, Trinity College Dublin, Dublin 2 (Ireland)
  3. (KTH), Electrum 229, Kista SE-16440 (Sweden)
  4. Institute for Applied Materials (IAM) and Karlsruhe Nano Micro Facility, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany)
  5. MATIS IMM-CNR, Universita' di Catania, Via S. Sofia 64, I-95123 Catania (Italy)
  6. Fraunhofer-Institut für Solare Energiesysteme ISE Heidenhofstr. 2, 79110 Freiburg (Germany)
  7. MIND-IN2UB, Departament d’Electrònica, Universitat de Barcelona, C/Martí i Franquès, 1, 08028 Barcelona (Spain)
  8. (Spain)
Publication Date:
OSTI Identifier:
22259294
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 114; Journal Issue: 18; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 77 NANOSCIENCE AND NANOTECHNOLOGY; ANNEALING; CHEMICAL VAPOR DEPOSITION; DIFFUSION BARRIERS; LAYERS; OPTICAL PROPERTIES; PHOTOLUMINESCENCE; PLASMA; QUANTUM DOTS; RED SHIFT; SILICA; SILICON; SILICON NITRIDES; SILICON OXIDES; SUPERLATTICES; THIN FILMS; TRANSMISSION ELECTRON MICROSCOPY; VENTILATION BARRIERS; X-RAY DIFFRACTION