Room Temperature Emission from Erbium Nanoparticles Embedded in a Silicon Matrix

1995 ◽  
Vol 405 ◽  
Author(s):  
A. Thilderkvist ◽  
J. Michel ◽  
S.-T. Ngiam ◽  
L. C. Kimerling ◽  
K. D. Kolenbrander
Keyword(s):  
Heat Treatment ◽  
Room Temperature ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Optically Active ◽  
Photoluminescence Intensity ◽  
Supersonic Expansion ◽  
Silicon Matrix ◽  
Room Temperature Photoluminescence ◽  
Expansion Technique

AbstractStrong room temperature photoluminescence emission from thin films of Er nanoparticles embedded in a matrix of silicon is reported. The Er nanoparticles were produced by a pulsed laser ablation supersonic expansion technique. After a heat treatment at 500°C in an Ar-atmosphere, intense Er-related luminescence appears at λ = 1.54 gim, characteristic of intra-4f emission from Er3÷. Only a 50% reduction in photoluminescence intensity is observed as the temperature increases from 4 K to 300 K. A photocarrier mediated process is responsible for the excitation of the optically active Er-centers.

Laser-Assisted Synthesis of Amorphous/Pseudoamorphous GaN Thin Films and Nanostructures

2006 ◽  
Vol 317-318 ◽  
pp. 585-588
Author(s):  
Seung Hwan Shim ◽  
Naoto Koshizaki ◽  
Jong Won Yoon ◽  
Kwang Bo Shim
Keyword(s):  
Thin Films ◽  
Heat Treatment ◽  
Laser Ablation ◽  
Chemical Composition ◽  
Room Temperature ◽  
Optical Band Gap ◽  
Laser Energy ◽  
Stoichiometric Composition ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation

Amorphous/pseudoamorphous GaN was prepared by pulsed-laser ablation at room temperature without any heat treatment. The structure and chemical composition of the specimens were systematically investigated. Laser ablation at low Ar pressure (<50Pa) led to deposition of smooth Ga-rich films, which is independent with laser energy. Under same pressures, as laser energy increased, the film stoichiometry changed from Ga-rich to near stoichiometric composition. Varying background Ar pressure strongly affected the product structure showing little effect on the chemical composition. Under higher pressure than 100 Pa, fine nanoparticles with a size of 5 nm rather than films were deposited on substrate due to the increased collision by plume confining. The optical band-gap of the deposited a-GaN is 2.8 eV for thin films and 3.9 eV for nanoparticles.

The Enabling Role of Surface Passivation in Visible Photoluminescence from Si Nanoparticles

1993 ◽  
Vol 318 ◽  
Author(s):  
A.A. Seraphin ◽  
E. Werwa ◽  
L.A. Chiu ◽  
K.D. Kolenbrander
Keyword(s):  
Room Temperature ◽  
Surface Passivation ◽  
Light Emission ◽  
Supersonic Expansion ◽  
Expansion Technique ◽  
Si Nanoparticles ◽  
Silicon Nanocrystallites ◽  
Pl Emission ◽  
Si Nanocrystallites

ABSTRACTSilicon nanocrystallites have been studied in a variety of passivating environments to study the role of surface passivation in visible light emission from the particles. Thin films of Si nanocrystallites have been deposited by a laser ablation supersonic expansion technique. The films show significant room temperature photoluminescence (PL) behavior only after processing to achieve surface passivation. Passivation effects on light emission are studied through PL emission spectroscopy on clusters in the gas phase, as well as films in a variety of passivating media. The intensity of PL emission seems to scale with the extent of surface passivation, but the specific nature of the passivating species is not critical in defining the wavelength of emitted light.

Early stages of the growth of BaTiO3 thin films studied by Transmission Electron Microscopy

1990 ◽  
Vol 48 (4) ◽  
pp. 706-707
Author(s):  
M. Grant Norton ◽  
Gerald R. English ◽  
Christopher Scarfone ◽  
C. Barry Carter
Keyword(s):  
Thin Films ◽  
Laser Ablation ◽  
Room Temperature ◽  
High Temperature Superconductors ◽  
Pulsed Laser ◽  
Target Material ◽  
Pulsed Laser Ablation ◽  
Cubic Phase ◽  
Transmission Electron ◽  
Tetragonal Form

Barium titanate (BaTiO3) may be used in a number of thin-film applications in electronic and optoelectronic devices. For these devices the formation of epitactic films of the correct stoichiometry and phase is essential. In particular, the tetragonal form of BaTiO3, which is stable at room temperature, exhibits ferro-, pyro- and piezoelectric properties. It is desirable to form films of the tetragonal phase directly and thus to avoid formation of either amorphous or polycrystalline material or to form material of the non-ferroelectric cubic phase. Recently two techniques, pulsed-laser ablation and reactive evaporation, have been used to form BaTiO3 thin-films. In the present study BaTiO3 thin-films have been formed using the pulsed-laser ablation technique. Pulsed-laser ablation is now widely used to produce thin-films of the high temperature superconductors and has many advantages over other techniques, in particular the formation of films which maintain the stoichiometry of the target material and by controlling the processing conditions the formation of films having defined crystalline phases.

Room temperature photoluminescence intensity enhancement in GaAs1-xBix alloys

2011 ◽  
Vol 9 (2) ◽  
pp. 259-261 ◽  
Author(s):  
A. R. Mohmad ◽  
F. Bastiman ◽  
J. S. Ng ◽  
S. J. Sweeney ◽  
J. P. R. David
Keyword(s):  
Room Temperature ◽  
Photoluminescence Intensity ◽  
Room Temperature Photoluminescence ◽  
Intensity Enhancement

Synthesis and processing of silicon nanocrystallites using a pulsed laser ablation supersonic expansion method

1994 ◽  
Vol 64 (14) ◽  
pp. 1821-1823 ◽  
Author(s):  
E. Werwa ◽  
A. A. Seraphin ◽  
L. A. Chiu ◽  
Chuxin Zhou ◽  
K. D. Kolenbrander
Keyword(s):  
Laser Ablation ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Expansion Method ◽  
Supersonic Expansion ◽  
Silicon Nanocrystallites ◽  
Synthesis And Processing

Strong room temperature 510 nm emission from cubic InGaN/GaN multiple quantum wells

2004 ◽  
Vol 831 ◽  
Author(s):  
S.F. Li ◽  
D.J. As ◽  
K. Lischka ◽  
D.G. Pacheco-Salazar ◽  
L.M.R. Scolfaro ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Room Temperature ◽  
Molecular Beam ◽  
Bandgap Energy ◽  
Multiple Quantum ◽  
Photoluminescence Intensity ◽  
Excitation Spectra ◽  
Room Temperature Photoluminescence ◽  
Double Heterostructures ◽  
Peak Energy

ABSTRACTCubic InGaN/GaN double heterostructures and multi-quantum-wells have been grown by Molecular Beam Epitaxy on cubic 3C-SiC. We find that the room temperature photoluminescence spectra of our samples has two emission peaks at 2.4 eV and 2.6 e V, respectively. The intensity of the 2.6 eV decreases and that of the 2.4 eV peak increases when the In mol ratio is varied between X = 0.04 and 0.16. However, for all samples the peak energy is far below the bandgap energy measured by photoluminescence excitation spectra, revealing a large Stokes-like shift of the InGaN emission. The temperature variation of the photoluminescence intensity yields an activation energy of 21 meV of the 2.6 eV emission and 67 meV of the 2.4 eV emission, respectively. The room temperature photoluminescence of fully strained multi quantum wells (x = 0.16) is a single line with a peak wavelength at about 510 nm.

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