X-ray double crystal diffraction and Raman spectra measurements of AlP/GaP short-period superlattices

AbstractThe optoelectronic properties of SimGen strained layer superlattices (SLS's) depend strongly on the structural perfection. We used double crystal and triple axis x-ray diffractometry to characterize the structural properties of short period Si9Ge6 SLS's grown on about lμm thick step-graded SiGe alloy buffers. As grown SLS's and samples annealed subsequently at 550°C, 650°C and 780°C for 60 mmn were investigated. Precise strain data were extracted from two-dimensional reciprocal space maps around (004) and (224) reciprocal lattice points. These data were used as refined input parameters for the dynamical simulation of the integrated intensity along the qll[004] direction. Annealing causes interdiffusion as indicated by the decreasing superlattice (SL)-satellite peak intensities and by the change of the Si/Ge thickness ratio. However, the full width at half maximum of the SL satellite peaks does not change significantly with annealing up to 650°C. The in-plane SL lattice constant in both samples is increased only slighty by annealing (< 9×10−3 Å). Consequently the interface intermixing due to interdiffusion is the main cause for the shift of the luminescence energy to higher values in these annealed samples.

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Double Periodicity Formation in EuTe/PbTe Superlattices

MRS Proceedings ◽

10.1557/proc-399-543 ◽

1995 ◽

Vol 399 ◽

Cited By ~ 3

Author(s):

M. Shima ◽

L. Salamanca-Riba ◽

G. Springholz ◽

G. Bauer

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

High Resolution ◽

Molecular Beam Epitaxy ◽

Molecular Beam ◽

X Ray Diffraction ◽

X Ray ◽

Transmission Electron ◽

Short Period ◽

Short Period Superlattices

ABSTRACTMolecular beam epitaxy was used to grow EuTe(x)/PbTe(y) short period superlattices with x=1-4 EuTe(111) monolayers alternating with y≈3x PbTe monolayers. The superlattices were characterized by transmission electron microscopy and high resolution x-ray diffraction. Regions with double periodicity were observed coexisting with areas of nominal periodicity. The sample with x=3.5 and y=9, for example, contains regions with double periodicity of x=7 and y=17. X-ray diffraction measurements confirm the formation of the double periodicity in these samples by the appearance of weak satellites in between the satellites of the nominal periodicity. The double periodicity in the superlattice is believed to result from interdiffusion during the growth. A model for this process is presented.

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Characterization of ultrathin Ge epilayers on (100) Si

Canadian Journal of Physics ◽

10.1139/p91-041 ◽

1991 ◽

Vol 69 (3-4) ◽

pp. 246-254 ◽

Cited By ~ 16

Author(s):

J. -M. Baribeau ◽

D. J. Lockwood ◽

T. E. Jackman ◽

P. Aebi ◽

T. Tyliszczak ◽

...

Keyword(s):

Strain Relaxation ◽

Three Dimensional ◽

Raman Scattering Spectroscopy ◽

X Ray ◽

Transmission Electron ◽

Short Period ◽

Short Period Superlattices ◽

Direct Band ◽

X Ray Absorption

The understanding of the epitaxy of pure Ge layers on Si is an important step towards the synthesis of SimGen (m, n < 10 monolayers) short-period superlattices. The possibility of a direct band-gap character makes these structures extremely attractive. We have grown thin buried Gen ([Formula: see text] monolayers) films on (100) Si by molecular beam epitaxy and studied their structural properties by a variety of techniques including Raman scattering spectroscopy, glancing incidence X-ray reflection, Rutherford backscattering, transmission electron microscopy, and extended X-ray absorption fine structure analysis. All these techniques allowed detection of the thin Ge layers and provided information about the thickness, morphology, strain distribution, and interface sharpness of these heterostructures. The Ge„ films with [Formula: see text] had a two-dimensional nature and showed no sign of strain relaxation. Intermixing at the Si–Ge interfaces was present in all these films and estimated to be not more than two monolayers. This smearing at the interfaces may have contributed to the maintenance of that pseudomorphicity. A thicker Ge layer (n = 12) showed evidence of strain relaxation and clustering in three-dimensional islands.

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Characterization of Interfacial Structure of InGaAs/InP Short Period Superlattices by Raman Scattering and High Resolution X-Ray Diffraction

MRS Proceedings ◽

10.1557/proc-324-285 ◽

1993 ◽

Vol 324 ◽

Cited By ~ 1

Author(s):

Teruo Mozume

Keyword(s):

Raman Scattering ◽

Long Range ◽

Range Order ◽

Interfacial Structure ◽

Long Range Order ◽

X Ray Diffraction ◽

X Ray ◽

Gas Source ◽

Short Period ◽

Short Period Superlattices

AbstractThe x-ray diffraction (XRD) of InGaAs/InP short-period superlattices (SPSL's) grown on (001)InP substrates by gas source molecular beam epitaxy (GSMBE) and by gas source migration enhanced epitaxy (GSMEE) shows that the GSMBE grown SPSL is strain free, and that GSMEE grown SPSL's with InGa-P and In-As heterointerfaces have strain-induced zerothorder satellite peak shift consistent with that in simulation results for the InGaAs/InP SPSL with one monolayer of InGaP and InAs inserted in each interface. Partial destruction of the long-range order is confirmed by the observation of the extra diffraction peak in GSMBE grown SPSL and by weak intensity of satellite peaks and nonuniform spacing between satellite peaks in GSMEE grown SPSL's. Raman scattering shows that the strain is accommodated in the interface layer in GSMEE grown samples. A confinement model without interface disorder fits the GaAs LO phonon very well. These results indicate that the local atomic arrangements are tailored by GSMEE, but that long range-order is impaired by the misfit dislocations in GSMEE grown SPSL's and by the exchange between As to P at the interfaces in GSMBE grown SPSL.

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Growth and characterization by X-ray diffraction of GaP/InP short-period superlattices

Journal of Crystal Growth ◽

10.1016/0022-0248(94)90732-3 ◽

1994 ◽

Vol 135 (1-2) ◽

pp. 123-128 ◽

Cited By ~ 1

Author(s):

A. Mazuelas ◽

A. Ruiz

Keyword(s):

X Ray Diffraction ◽

X Ray ◽

Short Period ◽

Short Period Superlattices

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X-ray standing wave studies of strained InxGa1−xAs/InP short-period superlattices

Journal of Applied Physics ◽

10.1063/1.1562736 ◽

2003 ◽

Vol 93 (9) ◽

pp. 5307-5315 ◽

Cited By ~ 1

Author(s):

Carmela Aruta ◽

Carlo Lamberti ◽

Luigi Gastaldi ◽

Federico Boscherini

Keyword(s):

Standing Wave ◽

X Ray ◽

Short Period ◽

Short Period Superlattices

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X-Ray Characterization of Nanostructured Semiconductor Short-Period Superlattices

MRS Proceedings ◽

10.1557/proc-749-w20.2 ◽

2002 ◽

Vol 749 ◽

Author(s):

Jianhua Li ◽

S. C. Moss ◽

V. Holy ◽

A.G. Norman ◽

A. Mascarenhas ◽

...

Keyword(s):

Film Growth ◽

Substrate Surface ◽

Cost Effective ◽

Mbe Growth ◽

X Ray ◽

Composition Modulation ◽

Global Strain ◽

Cost Effective Approach ◽

Short Period ◽

Short Period Superlattices

ABSTRACTSpontaneous lateral composition modulation during semiconductor thin film growth offers a particularly versatile and cost-effective approach to manufacture nanoscale devices. Recent experimental and theoretical studies have revealed that regular lateral composition modulation can be achieved via MBE growth of the so-called short-period superlattices and can be optimized via appropriate control of the global strain, substrate surface, and processing conditions. To characterize this phenomenon, we used synchrotron x-ray scattering to identify the interfacial morphology and laterally modulated composition profile of nearly strain-balanced InAs/AlAs short-period superlattices. Our results were compared with a theoretical model. It is shown that the lateral composition modulation is predominately caused by a vertically correlated morphlogical undulation of the superlattice layers.

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Spontaneous lateral modulation in short-period superlattices investigated by grazing-incidence x-ray diffraction

Physical Review B ◽

10.1103/physrevb.72.035313 ◽

2005 ◽

Vol 72 (3) ◽

Cited By ~ 2

Author(s):

O. Caha ◽

P. Mikulík ◽

J. Novák ◽

V. Holý ◽

S. C. Moss ◽

...

Keyword(s):

Grazing Incidence ◽

X Ray Diffraction ◽

X Ray ◽

Short Period ◽

Short Period Superlattices

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Interface Structure of Ge/Si Superlattices Determined by X-Ray Absorption Fine Structure

MRS Proceedings ◽

10.1557/proc-220-253 ◽

1991 ◽

Vol 220 ◽

Author(s):

P. Aebi ◽

T. Tyliszczak ◽

A. P. Hitchcock ◽

J. -M. Baribeau ◽

D. J. Lockwood ◽

...

Keyword(s):

Fine Structure ◽

Bond Length ◽

Strained Si ◽

Raman Scattering Spectroscopy ◽

X Ray ◽

Absorption Fine ◽

Nearest Neighbours ◽

Short Period ◽

Short Period Superlattices ◽

X Ray Absorption

ABSTRACTWe illustrate the usefulness of the Extended X-ray Absorption Fine Structure (EXAFS) technique to determine the amount of interface mixing and strain condition in the study of (SimGen)p short-period superlattices. It is found that for n < 4, the number of Ge and Si nearest neighbours to Ge atoms is consistent with ∼25% interfacial mixing and that the Ge-Ge bond length corresponds to that of coherently strained Ge. The Si-Ge bond length is shorter, close to that of a strained Si0.25Ge0.75 alloy. For n > 4, the Ge-Ge bond length and the number of Si-Ge nearest neighbours increase significantly consistent with partial relaxation and interdiffusion. Raman scattering spectroscopy and x-ray reflectometry measurements are also presented and are consistent with the conclusions of the EXAFS analysis.

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