Room Temperature Photoluminescence Spectra of Annealed PECVD Silicon Nitride Thin Films

1992 ◽  
Vol 284 ◽  
Author(s):  
C. Savall ◽  
E. Bustarret ◽  
J. P. Stoquert ◽  
J. C. Bruyére
Keyword(s):  
Silicon Nitride ◽  
Room Temperature ◽  
Visible Region ◽  
Broad Emission Band ◽  
Isochronous Annealing ◽  
Room Temperature Photoluminescence ◽  
Pl Spectra ◽  
Energy Part ◽  
Pl Spectrum ◽  
Deposited Film

ABSTRACTWe present the changes upon isochronous annealing in the room temperature photoluminescence (PL) spectra of nearly stoichiometric silicon nitride. Samples are prepared by the 50kHz PECVD of a N2/SiH4/Helium gas mixture at 350°C. In the as-deposited films the hydrogen content was around 11% for a refractive index of 1.98. For a photoexcitation at 351 nm, the polarized PL spectrum of the as-deposited film is characterized by a main broad emission band in the visible region with a maximum at 2.55eV. A second narrow peak (FWHM = 55meV), at 3.02eV is observed. We study the evolution of the PL spectra with different isochronous anneals from 350°C to 1000°C. Even though the general shape of the PL spectra does not change, we observe an increase of quantum efficiency with maximum value upon 750°C annealing. Beyond this temperature the low energy part of the PL spectrum shows a slight increase. These variations are compared to those of the infrared absorption peaks measured on the same samples. Both the temperature dependence of the intensity of a well defined absorption peak in the Si-H stretching mode region and that of the PL features can be explained assuming that solid state chemical reactions involving hydrogen and Si-Si bonds occur in the bulk of the alloy.

Degradation in a Methyl-phenyl Co-Polymeric Polysilane for LED Applications

2003 ◽  
Vol 769 ◽  
Author(s):  
Asha Sharma ◽  
Deepak ◽  
Monica Katiyar ◽  
Satyendra Kumar ◽  
V. Chandrasekhar ◽  
...  
Keyword(s):  
Thin Films ◽  
Molecular Weight ◽  
Light Source ◽  
Room Temperature ◽  
Light Exposure ◽  
Room Temperature Photoluminescence ◽  
Pl Spectrum ◽  
Pl Intensity ◽  
Methyl Phenyl

AbstractThe optical degradation of polysilane copolymer has been studied in spin cast thin films and solutions using light source of 325 nm wavelength. The room temperature photoluminescence (PL) spectrum of these films show a sharp emission at 368 nm when excited with a source of 325 nm. However, the PL intensity deteriorates with time upon light exposure. Further the causes of this degradation have been examined by characterizing the material for its transmission behaviour and changes occurring in molecular weight as analysed by GPC data.

Selected Synthesis of CuS Nanotubes and Hollow Nanospheres at Room Temperature

2007 ◽  
Vol 7 (12) ◽  
pp. 4501-4507 ◽  
Author(s):  
Xiaoyan Liu ◽  
Guangcheng Xi ◽  
Yankuan Liu ◽  
Shenglin Xiong ◽  
Lanlan Chai ◽  
...  
Keyword(s):  
Room Temperature ◽  
Hollow Spheres ◽  
Systematic Investigation ◽  
Distilled Water ◽  
Hollow Nanospheres ◽  
Room Temperature Photoluminescence ◽  
Pl Spectra ◽  
Factors Influencing ◽  
Solution Route ◽  
Structural Characterizations

A solution route has been developed to synthesize covellite (CuS) nanostructures through the precitation reaction of CuCl2 · 2H2O, thiourea (Tu), and NaHCO3 in distilled water at room temperature. By regulating the concentration of Tu, CuS nanotubes and hollow nanospheres with diameters of 100–200 nm have been selectively prepared. Structural characterizations indicate that both nanotubes and hollow spheres are composed of CuS nanoparticles with diameters of about 5–10 nm. UV-Vis absorption and room temperature photoluminescence (PL) spectra display different morphology-related absorption phenomena for nanotubes and hollow nanospheres. A systematic investigation has been carried out to understand the factors influencing the CuS morphology. Two different routes are identified to explain the formation of the nanotubes and hollow nanospheres herein.

Room-Temperature Photoluminescence Observation of Stacking Faults in 3C-SiC

2010 ◽  
Vol 645-648 ◽  
pp. 355-358 ◽  
Author(s):  
Rii Hirano ◽  
Michio Tajima ◽  
Kohei M. Itoh
Keyword(s):  
Silicon Carbide ◽  
Optical Properties ◽  
Room Temperature ◽  
Stacking Faults ◽  
Room Temperature Photoluminescence ◽  
Pl Spectra ◽  
Intensity Mapping ◽  
Pl Mapping ◽  
Pl Intensity ◽  
Cubic Silicon Carbide

We investigated the optical properties of stacking faults (SFs) in cubic silicon carbide by photoluminescence (PL) spectroscopy and mapping. The room-temperature PL spectra consisted of a 2.3 eV peak due to nitrogen and two undefined broad peaks at 1.7 eV and 0.95 eV. On the PL intensity mapping for the 2.3 eV peak, SFs appeared as dark lines. SFs which expose carbon atoms (SFC) and silicon atoms (SFSi) on the surface appeared as bright lines and dark lines, respectively, in PL mapping for the 1.7 eV and 0.95 eV peaks. We believe the two undefined peaks are associated with SFC. This technique allows us to detect SFs nondestructively and to distinguish between SFC and SFSi. We further suggest the presence of inhomogeneous stress around SFCs based on the broadening of the 2.3 eV peak.

Photoluminescence Properties of Sm3+-Doped La2O3 Powders

2011 ◽  
Vol 399-401 ◽  
pp. 967-972
Author(s):  
Qi Xiao ◽  
Gao Yuan Zhu
Keyword(s):  
Room Temperature ◽  
Optical Emission ◽  
Precipitation Method ◽  
Photoluminescence Properties ◽  
Light Emitting ◽  
Room Temperature Photoluminescence ◽  
Pl Spectra ◽  
Red Phosphors ◽  
Near Ultraviolet ◽  
Forbidden Transitions

The Sm3+-Doped La2O3powders were prepared by precipitation method. The room temperature photoluminescence (PL) spectra of Sm3+-Doped La2O3powders doped with different Sm3+concentration excited at 405 nm have been investigated. The PL spectra showed three main strong emissions peaks at near 572, 613, and 657 nm, which were due to the f-f forbidden transitions of the 4f electrons of Sm3+, corresponding to4G5/2→6H5/2(572 nm),6H7/2(613 nm), and6H9/2(657 nm), respectively. The optimum Sm3+concentration in La2O3powders for optical emission was determined to be 2.0 %. Since the 2% Sm-doped La2O3 offer a rather strong f–f transition excitation in near the UV region, the as-prepared phosphors are likely to be used as potential red phosphors for near-ultraviolet (370-410 nm) light-emitting diodes (LEDs).

Effect of trytophan as dopant on potassium acid phthalate single crystals

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Single Crystals ◽  
Room Temperature ◽  
Visible Region ◽  
X Ray Diffraction ◽  
X Ray ◽  
Slow Evaporation Technique ◽  
Absorption Studies ◽  
Evaporation Technique ◽  
Potassium Acid Phthalate ◽  
Acid Phthalate

Optically transparent single crystals of potassium acid phthalate (KAP, 0.5 g) 0.05 g and 0.1 g (1 and 2 mol %) trytophan were grown in aqueous solution by slow evaporation technique at room temperature. Single crystal X- ray diffraction analysis confirmed the changes in the lattice parameters of the doped crystals. The presence of functional groups in the crystal lattice has been determined qualitatively by FTIR analysis. Optical absorption studies revealed that the doped crystals possess very low absorption in the entire visible region. The dielectric constant has been studied as a function of frequency for the doped crystals. The thermal stability was evaluated by TG-DSC analysis.

Anomalous Room-Temperature Photoluminescence from Nanostrained MoSe2 Monolayers

ACS Photonics ◽  
2021 ◽  
Author(s):  
Tomojit Chowdhury ◽  
Kiyoung Jo ◽  
Surendra B. Anantharaman ◽  
Todd H. Brintlinger ◽  
Deep Jariwala ◽  
...  
Keyword(s):  
Room Temperature ◽  
Room Temperature Photoluminescence

Electrical and Optical Properties of Si+ and P+ Implanted InP:Fe

1990 ◽  
Vol 201 ◽  
Author(s):  
Honglie Shen ◽  
Genqing Yang ◽  
Zuyao Zhou ◽  
Guanqun Xia ◽  
Shichang Zou
Keyword(s):  
Optical Properties ◽  
Silicon Nitride ◽  
Temperature Dependence ◽  
Optimal Condition ◽  
Room Temperature ◽  
Broad Band ◽  
Photoluminescence Spectra ◽  
Electrical And Optical Properties ◽  
Spectrum Measurement ◽  
Single Implant

AbstractDual implantations of Si+ and P+ into InP:Fe were performed both at 200°C and room temperature. Si+ ions were implanted by 150keV with doses ranging from 5×1013 /cm2 to 1×1015 /cm2, while P+ ions were implanted by 110keV. 160keV and 180keV with doses ranging from 1×l013 /cm2 to 1×1015 /cm2. Hall measurements and photoluminescence spectra were used to characterize the silicon nitride encapsulated annealed samples. It was found that enhanced activation can be obtained by Si+ and P+ dual implantations. The optimal condition for dual implantations is that the atomic distribution of implanted P overlaps that of implanted si with the same implant dose. For a dose of 5×l014 /cm2, the highest activation for dual implants is 70% while the activation for single implant is 40% after annealing at 750°C for 15 minutes. PL spectrum measurement was carried out at temperatures from 11K to 100K. A broad band at about 1.26eV was found in Si+ implanted samples, of which the intensity increased with increasing of the Si dose and decreased with increasing of the co-implant P+ dose. The temperature dependence of the broad band showed that it is a complex (Vp-Sip) related band. All these results indicate that silicon is an amphoteric species in InP.

The Study on Microstructural and Optical Properties of Nanocrystalline Germanium Films

2010 ◽  
Vol 663-665 ◽  
pp. 324-327
Author(s):  
Chao Song ◽  
Rui Huang
Keyword(s):  
Multilayer Structure ◽  
Room Temperature ◽  
Multilayer Film ◽  
Volume Fraction ◽  
Raman Scattering Spectroscopy ◽  
Force Microscopy ◽  
Room Temperature Photoluminescence ◽  
Atomic Force ◽  
Lower Volume Fraction ◽  
Lower Volume

The germanium film and Ge/Si multilayer structure were fabricated by magnetron sputtering technique on silicon substrate at temperatures of 500°C. Raman scattering spectroscopy measurements reveal that the nanocrystalline Ge occurs in both kinds of samples. Furthermore, from the atomic force microscopy (AFM) results, it is found that the grain size as well as spatially ordering distribution of the nc-Ge can be modulated by the Ge/Si multilayer structure. The room temperature photoluminescence was also observed in the samples. However, compared with that from the nc-Ge film, the intensity of PL from the nc-Ge/a-Si multilayer film becomes weaker, which is attributed to its lower volume fraction of crystallized component.

scholarly journals Enhanced Room‐Temperature Photoluminescence Quantum Yield in Morphology Controlled J‐Aggregates

2021 ◽  
pp. 1903080
Author(s):  
Surendra B. Anantharaman ◽  
Joachim Kohlbrecher ◽  
Gabriele Rainò ◽  
Sergii Yakunin ◽  
Thilo Stöferle ◽  
...  
Keyword(s):  
Quantum Yield ◽  
Room Temperature ◽  
Room Temperature Photoluminescence ◽  
Photoluminescence Quantum Yield ◽  
J Aggregates
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