X-Ray Scattering (Modeling and Experiment) of InxGa1-xAs/GaAs Multiple Quantum Wells

1987 ◽  
Vol 103 ◽  
Author(s):  
Jichai Jeong ◽  
J. C. Lee ◽  
M. A. Shahid ◽  
T. E. Schlesinger ◽  
A. G. Milnes
Keyword(s):  
Quantum Well ◽  
Quantum Wells ◽  
Multiple Quantum ◽  
X Ray Diffraction ◽  
Quantum Well Structures ◽  
X Ray ◽  
X Ray Scattering ◽  
Transmission Electron ◽  
Diffraction Patterns ◽  
Good Agreement

ABSTRACTX-ray diffraction, transmission electron microscopy (TEM), and photoluminescence measurements have been made on strained InxGa1-xAs/GaAs quantum well structures. The well widths measured from TEM are 187, 115 and 69 Å for an interrupted growth, and 218, 126, 60 Å for a non-interrupted growth. In the measured x-ray diffraction patterns, the Pendellosung fringes due to GaAs barriers are modulated by a broad weak peak mostly coming from the thickest InxGa1-xAs well layer and is fairly symmetric for the noninterrupted sample. For the interrupted quantum well, the x-ray diffraction pattern is less symmetric, since there is further modulation by another broader and weaker peak. This results show that the In content in the InxGa1-xAs well layers are not well controlled for the interrupted quantum well. Using actual thickness measured from TEM, x-ray diffraction patterns are calculated and good agreement is obtained between the measured and the calculated x-ray diffraction patterns. The three strained InxGa1-xAs/Gaks quantum wells grown without interruption produce high intensity and narrow full-width at half-maximum (FWHIM) of 2.9 meV of the photoluminescence peak. The photoluminescence peaks for the interrupted quantum well are relatively broad and asymmetric, and have lower intensities, indicating that better quality InxGa1-xAs/GaAs quantum wells can be grown without interruption.

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.

Approaches Toward Chemically Prepared Multiple Quantum Well Structures

1998 ◽  
Vol 545 ◽  
Author(s):  
S. B. Cronin ◽  
T. Koga ◽  
X. Sun ◽  
Z. Ding ◽  
S.-C. Huang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Quantum Well ◽  
Quantum Wells ◽  
Self Assembly ◽  
Multiple Quantum Well ◽  
Multiple Quantum ◽  
X Ray Diffraction ◽  
Quantum Well Structures ◽  
Transmission Electron ◽  
2D System

AbstractAn enhanced thermoelectric figure of merit, ZT, has been predicted for Bi2Te3 in the form of 2-dimensional quantum wells. A new approach to making multiple quantum well (MQW) structures for thermoelectric applications utilizing a chemical intercalation technique is proposed and investigated. It is proposed that by starting from Li intercalated Bi2Te3 and Bi2Se3, the layers of these materials can be separated by chemical means. The layers of Bi2Te3 or Bi2 Se3 can then be restacked, by self-assembly, forming a non-periodic array of quantum wells. These chemically prepared MQWs are characterized by X-ray diffraction, SEM (scanning electron microscopy) and TEM (transmission electron microscopy) at various stages in the sample preparation to assess the degree to which the actual samples match the proposal. Experimental measurements of the Seebeck coefficient (S) and the electrical conductivity (σ) were performed over a range of temperatures for the initial bulk materials. It is found that some of the steps in the proposed fabrication have been achieved but still much improvement is needed before any practical thermoelectric 2D-system can be provided.

Spontaneous Lateral Modulations in InAlAs Buffer Layers Grown by MBE on InP Substrates

1995 ◽  
Vol 417 ◽  
Author(s):  
F. Peiró ◽  
A. Cornet ◽  
J. C. Ferrer ◽  
J. R. Morante ◽  
G. Halkias ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Molecular Beam ◽  
Buffer Layers ◽  
Single Quantum ◽  
X Ray Diffraction ◽  
Single Quantum Well ◽  
Quantum Well Structures ◽  
X Ray ◽  
Transmission Electron ◽  
Inp Substrates

AbstractTransmission Electron Microscopy (TEM) and X-ray Diffraction (XRD) have been used to analyze the spontaneous appearance of lateral composition modulations in InyAl1−yAs (yIn.≅ 50%) buffer layers of single quantum well structures grown by molecular beam epitaxy on exact and vicinal (100) InP substrates, at growth temperatures in the range of 530°C–580°C. The influence of the growth temperature, substrate misorientation and epilayer mismatch on the InAlAs lateral modulation is discussed. The development of a self-induced quantum-wire like morphology in the In0.53Ga0.47As single quantum wells grown over the modulated buffers is also commented on.

High-Resolution X-ray Diffraction Analysis of p-Type Strained InGaAs/AlGaAs Multiple Quantum Well Structures

1999 ◽  
Vol 607 ◽  
Author(s):  
W. Shi ◽  
D. H. Zhang ◽  
T. Osotchan ◽  
P.H. Zhang ◽  
S. F. Yoon ◽  
...  
Keyword(s):  
Quantum Well ◽  
Doping Concentration ◽  
Multiple Quantum Well ◽  
Multiple Quantum ◽  
X Ray Diffraction ◽  
Doping Density ◽  
Quantum Well Structures ◽  
As Doping ◽  
Transmission Electron ◽  
P Type

AbstractBe-doped InGaAs/AIGaAs multiple quantum well (MQW) structures, grown by solid-source molecular beam epitaxy with different doping concentration in the wells, were investigated by xray diffraction and transmission electron microscopy (TEM). Some features have been observed. (1) The MQW mean mismatch increases from 1.176 × 10−3 to 1.195 × 10−3 and 1.29 × 10−3 for the structures with doping concentration of 1 × 1017 cm−3, 1 × 1018cm−3and 2 × 1019 cm−3 in the wells, respectively. (2) The period of the MQW also increases with doping density. (3) The intensity of the first order satellite in the rocking curves decreases as the Be concentration is increased, indicating that indium diffusion in the heavily doped wells is likely more significant than that in the lightly doped ones. (4) The full width at half maximum of the zero-order satellite peak becomes widened as doping concentration increases, indicating that high Be-doping in the well likely deteriorates the interfaces of the multiple quantum well stacks. In addition, TEM measurement is conducted and clear pictures on well and barrier layers of the structures are observed. The information obtained is of great value for the design of p-doped quantum well infrared photodetectors.

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.

Mbe Growth of Strained-Layer InSb/InAlSb Structures

1990 ◽  
Vol 198 ◽  
Author(s):  
C.R. Whitehouse ◽  
C.F. Mcconville ◽  
G.M. Williams ◽  
A.G. Cullis ◽  
S.J. Barnett ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Critical Thickness ◽  
Multiple Quantum ◽  
Material System ◽  
X Ray Diffraction ◽  
Mbe Growth ◽  
X Ray ◽  
Strained Layer ◽  
Transmission Electron ◽  
Layer Structures

ABSTRACTThe MBE growth and related materials characterisation of InSb/InAlSb strained-layer structures is described. Band-gap considerations and critical thickness calculations are presented and indicate that this material system should offer considerable device potential. Detailed structural studies, performed using both transmission electron microscopy and X-ray diffraction, confirm the growth of high quality multiple quantum-wells, and 2K photoluminescence has shown corresponding energy upshifted transitions.

Growth and Characterization of AlGaN/GaN Heterostructures with Multiple Quantum Wells by PAMBE

1996 ◽  
Vol 423 ◽  
Author(s):  
K. H. Shim ◽  
J. M. Myoung ◽  
O. V. Gluschenkov ◽  
C. Kim ◽  
K. Kim ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Molecular Beam ◽  
Functional Dependence ◽  
Multiple Quantum Wells ◽  
Multiple Quantum ◽  
X Ray Diffraction ◽  
Structural And Optical Properties ◽  
X Ray ◽  
Good Agreement

AbstractAlGaN/GaN heterostructures with multiple quantum wells were grown by plasmaassisted molecular beam epitaxy (PAMBE). Structural and optical properties of the heterostructures were analyzed using x-ray diffraction, cathodoldminescence, and photoluminescence. Interband transitions were clearly observed in the GaN quantum wells at both room- and liquid-helium temperatures. The efficiency of the interband recombination due to the confinement effect was greatly enhanced in the thinner quantum wells. The functional dependence of the interband peaks on the well thickness is shown to be in good agreement with the calculated positions of the quantized levels in the wells.

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