High Luminescence Efficiency from GaAsN Layers Grown by MBE with RF Nitrogen Plasma Source

2001 ◽  
Vol 692 ◽  
Author(s):  
Victor M. Ustinov ◽  
Nikolai A. Cherkashin ◽  
Nikolai A. Bert ◽  
Andrei F. Tsatsul'nikov ◽  
Alexei R. Kovsh ◽  
...  

Abstract(In)GaAsN based heterostructures have been found to be promising candidates for the active region of 1.3 micron VCSELs. However, (In)GaAsN bulk layers and quantum wells usually demonstrate lower photoluminescence intensity than their nitrogen-free analogues. Defects associated with lower temperature growth and N-related defects due to plasma cell operation and possible nonuniform distribution of nitrogen enhance the non-radiative recombination in N-contained layers. We studied the photoluminescence intensity of GaAsN layers as a function of N content in MBE grown samples using rf-plasma source. Increasing the growth temperature to as high as 520 °C in combination with the increase in the growth rate allowed us to avoid any N-related defects up to 1.5% of nitrogen. Low-temperature-growth defects can be removed by post-growth annealing. We achieved the same radiative efficiency of GaAsN samples grown at 520°C with that of reference layer of GaAs grown at 600°C. Compositional fluctuations in GaAsN layers lead to characteristic S-shape of temperature dependence of photoluminescence peak position and this feature is the more pronounced the higher the amount of nitrogen in GaAsN. Annealing reduces compositional fluctuations in addition to the increase in the photoluminescence intensity. The results obtained are important for further improving the characteristics of InGaAsN lasers emitting at 1.3 micron.

2000 ◽  
Vol 5 (S1) ◽  
pp. 474-480 ◽  
Author(s):  
Sylvia G. Spruytte ◽  
Christopher W. Coldren ◽  
Ann F. Marshall ◽  
Michael C. Larson ◽  
James S. Harris

Nitride-Arsenide materials were grown by molecular beam epitaxy (MBE) using a radio frequency (rf) nitrogen plasma. The plasma conditions that maximize the amount of atomic nitrogen versus molecular nitrogen were determined using the emission spectrum of the plasma. Under constant plasma source conditions and varying group III flux, the nitrogen concentration in the film is inversely proportional to the group III flux (i. e. the nitrogen sticking coefficient is unity). The relationship between nitrogen concentration in the film and lattice parameter of the film is not linear for nitrogen concentrations above 2.9 mole % GaN, indicating that some nitrogen is incorporated on other locations than the group V lattice sites. For films with these higher nitrogen concentrations, XPS indicates that the nitrogen exists in two configurations: a Gallium-Nitrogen bond and another type of nitrogen complex in which nitrogen is less strongly bonded to Gallium atoms. Annealing removes this nitrogen complex and allows some of the nitrogen to diffuse out of the film. Annealing also improves the crystal quality of GaAsN quantum wells.


2001 ◽  
Vol 693 ◽  
Author(s):  
T. K. Ng ◽  
S. F. Yoon ◽  
S. Z. Wang ◽  
W. K. Loke ◽  
W. J. Fan

AbstractGaNAs and GaInNAs growths are subjects of considerable interest due to its technological importance in long wavelength lasers emitting within the optical-fiber communication wavelength window (1.31 – 1.55 m m). We study GaNAs and GaInNAs materials growth on (100) semi-insulating GaAs substrate with high nitrogen compositions (>2%) using a solid source molecular beam epitaxy (SSMBE) system in conjunction with a RF plasma source. GaNAs layer with high nitrogen compositions of 4.85% and 6% with good XRD peak intensities were successfully grown. GaInNAs quantum wells (QWs) were then grown with reference to the nitrogen compositions measured in the GaNAs materials to obtain nitrogen compositions > 2%. The photoluminescence (PL) peak positions of the GaInNAs QWs blueshifted after annealing at 840°C and 10min. It was found that the blueshift of PL peaks are highly dependent on nitrogen compositions.


1992 ◽  
Vol 281 ◽  
Author(s):  
R. L. Gunshor ◽  
A. V. Nurmikko ◽  
N. Otsuka

ABSTRACTThe use of a nitrogen rf plasma source for p-type ZnSe grown by MBE, has allowed a variety of pn junction based devices to be realized. The pn junctions have been combined with (Zn,Cd)Se quantum wells to implement semiconductor injection lasers, operating in the blue/green portion of the spectrum, which were reported by 3M and the Brown/Purdue group in the summer of 1991. In the past year the field has moved rapidly. In particular, we can now report CW operation at low temperatures as well as pulsed operation at room temperature (490nm) using a Zn(S,Se)-based device configuration. Laser power output per facet for some designs is above 300 mW, and threshold current densities are as low as 1000A/cm 2 at room temperature. Lasing was demonstrated from devices grown on both p and n-type GaAs substrates. X-ray rocking curves of theII-VI regions exhibit FWHM values below 20 arcsec for specific samples. Dislocation densities are less than 105 cm−2, below the threshold of TEM plan view imaging. The blue LEDs provide power outputs in excess of 100μW while exhibiting external quantum efficiencies of 0.1% at room temperature.


Author(s):  
G.A. Westenskow ◽  
D.P. Grote ◽  
E. Halaxa ◽  
J.W. Kwan ◽  
W.L. Waldron

1999 ◽  
Vol 593 ◽  
Author(s):  
T. Thärigen ◽  
V. Riede ◽  
G. Lippold ◽  
E. Hartmann ◽  
R. Hesse ◽  
...  

ABSTRACTCarbon silicon nitride (CSixNy), and carbon boron nitride (CBxNy) thin films have been grown by pulsed laser deposition (PLD) of various carbon (silicon/boron) (nitride) targets using an additional nitrogen RF plasma source on [100] oriented silicon substrates without additional heating. The CSixNy and CBxNy thin films were amorphous and showed nano hardness up to 23 GPa compared to 14 GPa for silicon and maximum nitrogen content of 30 at%. The maximum nanohardness was achieved for 10% Si and 10% B content in the films. The lower hardness of this films compared to the nanohardness of 30-50 GPa of DLC films indicates a lower amount of covalent carbon-nitrogen bonding in the films. However, in contrast to DLC films, the CSixNy and CBxNy films can be grown to thickness above 3 μm due to lower internal compressive stress. XPS of CSixNy and CBxNy film surfaces shows clear correlation of binding energy and intensity of N ls, C ls, and Si 2p peaks to composition of the PLD-targets and to nitrogen flow through plasma source, indicating soft changes of binding structure due to variation of PLD parameters. The results demonstrate the capability of the plasma assisted PLD process to deposit hard amorphous CSixNy, and CBxNy thin films with adjustable properties.


2005 ◽  
Vol 864 ◽  
Author(s):  
Homan B. Yuen ◽  
Robert Kudrawiec ◽  
K. Ryczko ◽  
S.R. Bank ◽  
M.A. Wistey ◽  
...  

AbstractHeterojunction band offsets of GaNAsSb/GaAs, GaInNAsSb/GaAs, and GaInNAsSb/GaNAs/GaAs quantum well (QW) structures were measured by photoreflectance (PR) spectroscopy. These samples were grown by solid-source molecular beam epitaxy using a radio-frequency nitrogen plasma source. PR spectra were collected from the QW structures and the energy transitions were obtained. The experimental data of the QW energy transitions were analyzed by theoretical calculations. Using predetermined values such as QW thickness and composition, unknown factors such as the heterojunction band offsets were able to be determined. For the GaN0.02As0.87Sb0.11/GaAs structure, we found that Qc≈0.5. For Ga0.62In0.38N0.026As0.954Sb0.02/GaAs, we found that Qc≈0.8. This value is similar to the antimony free dilute-nitride material GaInNAs since the small amount of antimony does not affect the band offsets. For the technologically important Ga0.61In0.39N0.023As0.957Sb0.02/GaN0.027As0.973/GaAs laser structure, we found that the GaInNAsSb/GaNAs QW had a conduction band offset of 144 meV and a valence band offset of 127 meV. With a greater understanding of the band structure, more advanced GaInNAsSb laser devices can be obtained.


2013 ◽  
Vol 1617 ◽  
pp. 43-48
Author(s):  
R. Cisneros Tamayo ◽  
I.J. Gerrero Moreno ◽  
A. Vivas Hernandez ◽  
J.L. Casas Espinola ◽  
L. Shcherbyna

ABSTRACTThe photoluminescence (PL), its temperature dependence and X-ray diffraction (XRD) have been studied in MBE grown GaAs/AlGaAs/InGaAs/AlGaAs /GaAs quantum wells (QWs) with InAs quantum dots embedded in the center of InGaAs layer in the freshly prepared states and after the thermal treatments during 2 hours at 640 or 710 °C. The structures contained two buffer (Al0.3Ga0.7As/In0.15Ga0.85As) and two capping (In0.15Ga0.85As / Al0.3Ga0.7As) layers. The temperature dependences of PL peak positions have been analyzed in the temperature range 10-500K with the aim to investigate the QD composition and its variation at thermal annealing. The experimental parameters of the temperature variation of PL peak position in the InAs QDs have been compared with the known one for the bulk InAs crystals and the QD composition variation due to Ga/Al/In inter diffusion at thermal treatments has been detected. XRD have been studied with the aim to estimate the capping/buffer layer compositions in the different QW layers in freshly prepared state and after the thermal annealing. The obtained emission and XRD data and their dependences on the thermal treatment have been analyzed and discussed.


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