scholarly journals Disordering of InGaN/GaN Superlattices after High-Pressure Annealing

1999 ◽  
Vol 4 (S1) ◽  
pp. 293-298
Author(s):  
M.D. McCluskey ◽  
L.T. Romano ◽  
B.S. Krusor ◽  
D. Hofstetter ◽  
D.P. Bour ◽  
...  
Keyword(s):  
Quantum Well ◽  
Secondary Ion Mass Spectrometry ◽  
Multiple Quantum Well ◽  
Blue Shift ◽  
Multiple Quantum ◽  
X Ray Diffraction ◽  
X Ray ◽  
Annealing Temperatures ◽  
Composition Profiles ◽  
Secondary Ion

Interdiffusion of In and Ga is observed in InGaN multiple-quantum-well superlattices for annealing temperatures of 1250 to 1400°C. Hydrostatic pressures of up to 15 kbar were applied during the annealing treatments to prevent decomposition of the InGaN and GaN. In as-grown material, x-ray diffraction spectra show InGaN superlattice peaks up to the fourth order. After annealing at 1400°C for 15 min, only the zero-order InGaN peak is observed, a result of compositional disordering of the superlattice. Composition profiles from secondary ion mass spectrometry indicate significant diffusion of Mg from the p-type GaN layer into the quantum well region. This Mg diffusion may lead to an enhancement of superlattice disordering. For annealing temperatures between 1250 and 1300°C, a blue shift of the InGaN spontaneous emission peak is observed, consistent with interdiffusion of In and Ga in the quantum-well region.

scholarly journals Disordering of InGaN/GaN Superlattices After High-Pressure Annealing

1998 ◽  
Vol 537 ◽  
Author(s):  
M.D. McCluskey ◽  
L.T. Romano ◽  
B.S. Krusor ◽  
D. Hofstetter ◽  
D.P. Bour ◽  
...  
Keyword(s):  
Quantum Well ◽  
Secondary Ion Mass Spectrometry ◽  
Multiple Quantum Well ◽  
Blue Shift ◽  
Multiple Quantum ◽  
X Ray Diffraction ◽  
X Ray ◽  
Annealing Temperatures ◽  
Composition Profiles ◽  
Secondary Ion

AbstractInterdiffusion of In and Ga is observed in InGaN multiple-quantum-well superlattices for annealing temperatures of 1250 to 1400°C. Hydrostatic pressures of up to 15 kbar were applied during the annealing treatments to prevent decomposition of the InGaN and GaN. In as-grown material, x-ray diffraction spectra show InGaN superlattice peaks up to the fourth order. After annealing at 1400°C for 15 min, only the zero-order InGaN peak is observed, a result of compositional disordering of the superlattice. Composition profiles from secondary ion mass spectrometry indicate significant diffusion of Mg from the p-type GaN layer into the quantum well region. This Mg diffusion may lead to an enhancement of superlattice disordering. For annealing temperatures between 1250 and 1300°C, a blue shift of the InGaN spontaneous emission peak is observed, consistent with interdiffusion of In and Ga in the quantum-well region.

Growth and Characterization of Deep UV Emitter Structures Grown on Single Crystal Bulk AlN Substrates

2002 ◽  
Vol 743 ◽  
Author(s):  
X. Hu ◽  
R. Gaska ◽  
C. Chen ◽  
J. Yang ◽  
E. Kuokstis ◽  
...  
Keyword(s):  
Quantum Well ◽  
Single Crystal ◽  
Multiple Quantum Well ◽  
Blue Shift ◽  
Stimulated Emission ◽  
Localized States ◽  
Light Sources ◽  
Multiple Quantum ◽  
X Ray ◽  
Deep Uv

ABSTRACTWe report on high Al-content AlGaN-based deep UV emitter structures grown over single crystal, slightly off c-axis (5.8 degrees) bulk AlN substrates. AlN/AlGaN multiple quantum well (MQW) structures with up to 50% of Al in the well material were grown by using low-pressure MOCVD and characterized by using X-ray, AFM, SEM and photoluminescence techniques. Two light sources, one at 213 nm wavelength for selective excitation of quantum well layers and another one at 193 nm to excite both wells and barriers, were exploited. A weak temperature dependence (from 8 K to 300 K) of the luminescence intensity and the absence of blue-shift of the luminescence peak with increasing excitation intensity pointed to a low density of localized states, in a good agreement with the X-ray data, which indicated very high quality of these MQW structures.The most striking result was observation of stimulated emission at wavelength as short as 258 nm in Al0.5Ga0.5N/AlN MQWs grown on bulk AlN single crystals.

High Resolution X-ray Diffraction Characterization of [111]B Oriented InGaAs/GaAs Mqw Structures

1995 ◽  
Vol 39 ◽  
pp. 439-448
Author(s):  
A Sanz-Hervas ◽  
A Sacedón ◽  
E.J Abril ◽  
J.L Sanchez-Rojas ◽  
C. Villar ◽  
...  
Keyword(s):  
High Resolution ◽  
Quantum Well ◽  
Structural Information ◽  
Multiple Quantum Well ◽  
Growth Conditions ◽  
Multiple Quantum ◽  
X Ray Diffraction ◽  
Quantum Well Structures ◽  
X Ray

In this work we apply high-resolution X-ray diffractometry to the study of InGaAs/GaAs multiple quantum well structures on (001) and(lll)B GaAs substrates. The samples consisted of p-i-n diodes with a multiple quantum well embedded in the i-region and were simultaneously grown on (001) and (111)B substrates by molecular beam epitaxy. For the characterization we have used symmetric and asymmetric reflections at different azimuthal positions. The interpretation of the diffraction profiles has been possible thanks to our recently developed simulation model, which allows the calculation of any reflection regardless of the substrate orientation. X-ray results about composition and thickness are very similar in the samples simultaneously grown on both orientations as expected from our specific growth conditions. The information obtained from X-ray characterization is consistent with the results of photoluminescence and photocurrent measurements within the experimental uncertainty of the techniques. In (lll)B samples, X-ray diffractometry provides structural information which cannot be easily obtained from optical characterization techniques.

Growth and Characterization Of GexSi1−x/ Si Multiple Quantum Well Structures

1992 ◽  
Vol 263 ◽  
Author(s):  
D.W. Greve ◽  
R. Misra ◽  
M.A. Capano ◽  
T.E. Schlesinger
Keyword(s):  
Quantum Well ◽  
Quantum Wells ◽  
Multiple Quantum Well ◽  
Small Variation ◽  
Multiple Quantum ◽  
X Ray Diffraction ◽  
High Quality ◽  
Quantum Well Structures ◽  
X Ray

ABSTRACTWe report on the growth and characterization of multiple quantum well structures by UHV/ CVD epitaxy. X- ray diffraction is used to verify the expected layer periodicity and to determine the quantum well thickness. Photoluminescence measurements show peaks which we associate with recombination of excitons in the quantum wells. The measurements are consistent with high quality layers with small variation in quantum well thickness across a wafer.

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