Strong Room Temperature Blue Emission from Rapid Thermal Annealed Cerium-Doped Aluminum (Oxy)Nitride Thin Films

Cerium-doped aluminum nitride (Ce-AlN) thin films were prepared at room temperature (RT) using radio frequency (RF) reactive sputtering. As-deposited samples were then subjected to rapid thermal annealing (RTA). X-ray diffraction and high resolution transmission electron microscopy (HRTEM) revealed a well crystalline textured microstructure with single [002] out-of-plane orientation in both as-deposited and annealed samples. Strong RT blue emission from post-annealed samples was detected under optical excitation either by 325 or 266 nm cw lasers. Electron energy loss spectroscopy (EELS) measurements at the Ce edges reveal the dominant oxidation state of Ce atoms, which undergoes a change from of Ce to Ce ions after RTA annealing in Ar atmosphere. The chemical composition was analyzed by Rutherford backscattering spectrometry (RBS) and contrasted to HRTEM images. Our findings indicate that the surface oxidation during the post-deposition annealing in Ar plays an important role in the PL response by changing the oxidation state of Ce ions from optically inactive ions (Ce) to the optically active ones (Ce). Moreover, the importance of this oxidation is further confirmed by the excitation mechanisms responsible for the blue emission determined by PL excitation measurements.https://doi.org/10.1021/acsphotonics.7b00233Alaa E. Giba thanks Erasmus mundus scholarship that financially funded this work within the DocMASE program. He also thanks the Université franco-allemande (UFA) for supporting his travel and stay to Saarland University within the Ph.D. track in Materials Science and Engineering. Financial support from Grant P2013/MIT-2775 (Comunidad Autónoma de Madrid, Spain) is greatly acknowledged

Heavily doped Si-nanocrystals formed in P-(SiO/SiO2) multilayers: a novel route to infrared Si-based plasmonics

As building blocks of novel multifunctional materials involving coupling at the nanoscale, highly doped semiconductor nanocrystals are of great interest for potential applications in nanophotonics. In this work, we investigate the plasmonic properties of highly doped Si nanocrystals embedded in a silica matrix. These materials are obtained by evaporation of heavily Phosphorus-doped SiO/SiO2 multilayers in a ultrahigh vacuum chamber followed by rapid thermal annealing. For P contents between 0.7 and 1.9 at%, structural investigations at the nanoscale give clear evidence that P atoms are mainly located in the core of Si nanocrystals with concentrations reaching up to 10 at%, i.e. well beyond the solid solubility limit of P in bulk Si. Alloying and formation of SiP nanoparticles is observed for P contents exceeding 4 at% in the multilayer. Infrared absorption measurements give evidence of a localized surface plasmon resonance located in the 3 to 6 µm range. A core-shell structure was used to model Si nanocrystals embedded in a silica matrix. Based on the Mie theory and the Drude model, both the mobility and the free charge carrier density were extracted from the simulation, with values reaching 27 cm2V-1s-1 and 2.3×1020 cm-3, respectively. This results in a dopant activation rate of about 8 %

Heavily doped Si-nanocrystals formed in P-(SiO/SiO2) multilayers: a novel route to infrared Si-based plasmonics

As building blocks of novel multifunctional materials involving coupling at the nanoscale, highly doped semiconductor nanocrystals are of great interest for potential applications in nanophotonics. In this work, we investigate the plasmonic properties of highly doped Si nanocrystals embedded in a silica matrix. These materials are obtained by evaporation of heavily Phosphorus-doped SiO/SiO2 multilayers in a ultrahigh vacuum chamber followed by rapid thermal annealing. For P contents between 0.7 and 1.9 at%, structural investigations at the nanoscale give clear evidence that P atoms are mainly located in the core of Si nanocrystals with concentrations reaching up to 10 at%, i.e. well beyond the solid solubility limit of P in bulk Si. Alloying and formation of SiP nanoparticles is observed for P contents exceeding 4 at% in the multilayer. Infrared absorption measurements give evidence of a localized surface plasmon resonance located in the 3 to 6 µm range. A core-shell structure was used to model Si nanocrystals embedded in a silica matrix. Based on the Mie theory and the Drude model, both the mobility and the free charge carrier density were extracted from the simulation, with values reaching 27 cm2V-1s-1 and 2.3×1020 cm-3, respectively. This results in a dopant activation rate of about 8 %

Heavily doped Si-nanocrystals formed in P-(SiO/SiO2) multilayers: a novel route to infrared Si-based plasmonics

As building blocks of novel multifunctional materials involving coupling at the nanoscale, highly doped semiconductor nanocrystals are of great interest for potential applications in nanophotonics. In this work, we investigate the plasmonic properties of highly doped Si nanocrystals embedded in a silica matrix. These materials are obtained by evaporation of heavily Phosphorus-doped SiO/SiO2 multilayers in a ultrahigh vacuum chamber followed by rapid thermal annealing. For P contents between 0.7 and 1.9 at%, structural investigations at the nanoscale give clear evidence that P atoms are mainly located in the core of Si nanocrystals with concentrations reaching up to 10 at%, i.e. well beyond the solid solubility limit of P in bulk Si. Alloying and formation of SiP nanoparticles is observed for P contents exceeding 4 at% in the multilayer. Infrared absorption measurements give evidence of a localized surface plasmon resonance located in the 3 to 6 µm range. A core-shell structure was used to model Si nanocrystals embedded in a silica matrix. Based on the Mie theory and the Drude model, both the mobility and the free charge carrier density were extracted from the simulation, with values reaching 27 cm2V-1s-1 and 2.3×1020 cm-3, respectively. This results in a dopant activation rate of about 8 %