X‐ray truncation rod study of Ge(001) surface roughening by molecular beam homoepitaxial growth

Recently, the GaSb/InAs superlattice system has received renewed attention. The interest stems from a model demonstrating that short period Ga1-xInxSb/InAs superlattices will have both a band gap less than 100 meV and high optical absorption coefficients, principal requirements for infrared detector applications. Because this superlattice system contains two species of cations and anions, it is possible to prepare either InSb-like or GaAs-like interfaces. As such, the system presents a unique opportunity to examine interfacial properties.We used molecular beam epitaxy (MBE) to prepare an extensive set of GaSb/InAs superlattices grown on an GaSb buffer, which, in turn had been grown on a (100) GaAs substrate. Through appropriate shutter sequences, the interfaces were directed to assume either an InSb-like or GaAs-like character. These superlattices were then studied with a variety of ex-situ probes such as x-ray diffraction and Raman spectroscopy. These probes confirmed that, indeed, predominantly InSb-like and GaAs-like interfaces had been achieved.

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Temperature dependence of surface roughening during homoepitaxial growth on Cu(001)

Physical Review B ◽

10.1103/physrevb.64.125427 ◽

2001 ◽

Vol 64 (12) ◽

Cited By ~ 20

Author(s):

C. E. Botez ◽

P. F. Miceli ◽

P. W. Stephens

Keyword(s):

Temperature Dependence ◽

Surface Roughening ◽

Homoepitaxial Growth

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Strain Shift Coefficients for Phonons in Si-Ge Heterostructures

MRS Proceedings ◽

10.1557/proc-239-449 ◽

1991 ◽

Vol 239 ◽

Cited By ~ 4

Author(s):

J.-M. Baribeau ◽

D. J. Lockwood

Keyword(s):

Molecular Beam ◽

Composition Dependence ◽

Vibration Mode ◽

Phonon Frequency ◽

Longitudinal Optical ◽

Stress Factor ◽

Double Crystal ◽

Raman Scattering Spectroscopy ◽

X Ray ◽

Shift Coefficient

ABSTRACTStrain shift coefficient measurements for longitudinal optical phonons in molecular beam epitaxy grown metastable pseudomorphic Si1−xGex layers on (100) Si (0 < x < 0.35) and Ge (0.80 < x < 1) are reported. Strain in partially relaxed annealed specimens was obtained by double-crystal x-ray diffractometry and the corresponding strain phonon shift was measured by Raman scattering spectroscopy. For epilayers grown on Si it was found that the epilayer Si-Si phonon frequency varies linearly with strain. The magnitude of the strain shift coefficient b however showed a small composition dependence varying from b ≈ -700 cm-1 at x = 0 to b ≈ -950 cm-1 at x = 0.35, corresponding to a stress factor τ = 0.40 + 0.57x: + 0.13x2 cm-1/kbar. For the Ge-Ge vibration mode in epilayers grown on Ge, b decreased from ∼-425 cm-1 at x = 1 to ∼-500 cm-1 at x = 0.8, corresponding to a stress factor τ ≈ 0.52 – 0.14x - 0.08x2 cm-1/kbar.

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Optical and structural prorerties of InAs epilayer on graded InGaAs

MRS Proceedings ◽

10.1557/proc-696-n3.10 ◽

2001 ◽

Vol 696 ◽

Author(s):

Gu Hyun Kim ◽

Jung Bum Choi ◽

Joo In Lee ◽

Se-Kyung Kang ◽

Seung Il Ban ◽

...

Keyword(s):

Molecular Beam Epitaxy ◽

Residual Strain ◽

Molecular Beam ◽

Lattice Mismatch ◽

Peak Position ◽

Excitation Intensity ◽

Total Thickness ◽

Ingaas Layer ◽

X Ray Diffraction ◽

X Ray

AbstractWe have studied infrared photoluminescence (PL) and x-ray diffraction (XRD) of 400 nm and 1500 nm thick InAs epilayers on GaAs, and 4 nm thick InAs on graded InGaAs layer with total thickness of 300 nm grown by molecular beam epitaxy. The PL peak positions of 400 nm, 1500 nm and 4 nm InAs epilayer measured at 10 K are blue-shifted from that of InAs bulk by 6.5, 4.5, and 6 meV, respectively, which can be largely explained by the residual strain in the epilayer. The residual strain caused by the lattice mismatch between InAs and GaAs or graded InGaAs/GaAs was observed from XRD measurements. While the PL peak position of 400 nm thick InAs layer is linearly shifted toward higher energy with increase in excitation intensity ranging from 10 to 140 mW, those of 4 nm InAs epilayer on InGaAs and 1500 nm InAs layer on GaAs is gradually blue-shifted and then, saturated above a power of 75 mW. These results suggest that adopting a graded InGaAs layer between InAs and GaAs can efficiently reduce the strain due to lattice mismatch in the structure of InAs/GaAs.

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Anisotropic Lattice Relaxation and its Mechanism of ZnSe Epilayer Grown on (001) GaAs Substrate by Molecular Beam Epitaxy

MRS Proceedings ◽

10.1557/proc-399-449 ◽

1995 ◽

Vol 399 ◽

Author(s):

C.S. Kim ◽

S.K. Noh ◽

H.J. Lee ◽

Y.K. Cho ◽

Y.I. Kim ◽

...

Keyword(s):

Dislocation Density ◽

Gaas Substrate ◽

Molecular Beam ◽

Rotation Angle ◽

Lattice Relaxation ◽

High Dislocation Density ◽

Sinusoidal Oscillation ◽

Double Crystal ◽

X Ray ◽

Anisotropic Lattice

ABSTRACTWe have investigated anisotropic lattice relaxation and its mechanism of ZnSe epitaxial layer grown on (001) GaAs substrate by MBE. Double-crystal X-ray rocking curves for (004), {115} and {404} reflections were measured as a function of the azimuthal rotation angle of the sample. We observed the sinusoidal oscillation of the FWHM of the epilayer peak for (004) reflections due to the asymmetric dislocation density along two orthogonal <110> directions, and the direction of the maximum FWHM corresponding to high dislocation density is along [110]. In addition, the strain along [110] is smaller than that along [1-10], indicating that the layer suffered anisotropic lattice relaxation. The direction of larger relaxation([l-10]) is not consistent with that of high dislocation density([110]). The results suggest that the asymmetry in dislocation density is not responsible for the anisotropic relaxation of the ZnSe epilayer.

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X-Ray Diffraction Study of Rare Earth Epitaxial Structures Grown by MBE onto (111) GaAs

MRS Proceedings ◽

10.1557/proc-151-277 ◽

1989 ◽

Vol 151 ◽

Author(s):

W. R. Bennett ◽

R. F. C. Farrow ◽

S. S. P. Parkin ◽

E. E. Marinero

Keyword(s):

Rare Earth ◽

Molecular Beam Epitaxy ◽

Rare Earth Metal ◽

Molecular Beam ◽

Earth Metal ◽

Magnetic Ordering ◽

Metal Films ◽

X Ray Diffraction ◽

X Ray ◽

Strain Components

ABSTRACTWe report on the new epitaxial system LaF3/Er/Dy/Er/LaF3/GaAs (111) grown by molecular beam epitaxy. X-ray diffraction studies have been used to determine the epitaxial relationships between the rare earths, the LaF3 and the substrate. Further studies of symmetric and asymmetric reflections yielded the in-plane and perpendicular strain components of the rare earth layers. Such systems may be used to probe the effects of magnetoelastic interactions and dimensionality on magnetic ordering in rare earth metal films and multilayers.

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A Study on the Growth of Cubic GaN Films Using an AlGaAs Buffer Layer Grown on GaAs (100) by Plasma-Assisted Molecular Beam Epitaxy

MRS Proceedings ◽

10.1557/proc-639-g3.46 ◽

2000 ◽

Vol 639 ◽

Author(s):

Ryuhei Kimura ◽

Kiyoshi Takahashi ◽

H. T. Grahn

Keyword(s):

Molecular Beam Epitaxy ◽

Buffer Layer ◽

Molecular Beam ◽

High Energy ◽

Rf Plasma ◽

Cubic Phase ◽

X Ray Diffraction ◽

X Ray ◽

Cubic Gan

ABSTRACTAn investigation of the growth mechanism for RF-plasma assisted molecular beam epitaxy of cubic GaN films using a nitrided AlGaAs buffer layer was carried out by in-situ reflection high energy electron diffraction (RHEED) and high resolution X-ray diffraction (HRXRD). It was found that hexagonal GaN nuclei grow on (1, 1, 1) facets during nitridation of the AlGaAs buffer layer, but a highly pure, cubic-phase GaN epilayer was grown on the nitrided AlGaAs buffer layer.

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Properties of Epitaxial SrTiO3 Thin Films Grown on Silicon by Molecular Beam Epitaxy

MRS Proceedings ◽

10.1557/proc-567-427 ◽

1999 ◽

Vol 567 ◽

Cited By ~ 23

Author(s):

Z. Yu ◽

R. Droopad ◽

J. Ramdani ◽

J.A. Curless ◽

C.D. Overgaard ◽

...

Keyword(s):

Thin Films ◽

Molecular Beam Epitaxy ◽

Molecular Beam ◽

High Energy ◽

State Density ◽

Unit Cell ◽

Ex Situ ◽

Silicon Oxide Layer ◽

Single Crystalline ◽

X Ray

ABSTRACTSingle crystalline perovskite oxides such as SrTiO3 (STO) are highly desirable for future generation ULSI applications. Over the past three decades, development of crystalline oxides on silicon has been a great technological challenge as an amorphous silicon oxide layer forms readily on the Si surface when exposed to oxygen preventing the intended oxide heteroepitaxy on Si substrate. Recently, we have successfully grown epitaxial STO thin films on Si(001) surface by using molecular beam epitaxy (MBE) method. Properties of the STO films on Si have been characterized using a variety of techniques including in-situ reflection high energy electron diffraction (RHEED), ex-situ X-ray diffraction (XRD), spectroscopic ellipsometry (SE), Auger electron spectroscopy (AES) and atomic force microscopy (AFM). The STO films grown on Si(001) substrate show bright and streaky RHEED patterns indicating coherent two-dimensional epitaxial oxide film growth with its unit cell rotated 450 with respect to the underlying Si unit cell. RHEED and XRD data confirm the single crystalline nature and (001) orientation of the STO films. An X-ray pole figure indicates the in-plane orientation relationship as STO[100]//Si[110] and STO(001)// Si(001). The STO surface is atomically smooth with AFM rms roughness of 1.2 AÅ. The leakage current density is measured to be in the low 10−9 A/cm2 range at 1 V, after a brief post-growth anneal in O2. An interface state density Dit = 4.6 × 1011 eV−1 cm−2 is inferred from the high-frequency and quasi-static C-V characteristics. The effective oxide thickness for a 200 Å STO film is around 30 Å and is not sensitive to post-growth anneal in O2 at 500-700°C. These STO films are also robust against forming gas anneal. Finally, STO MOSFET structures have been fabricated and tested. An extrinsic carrier mobility value of 66 cm2 V−11 s−1 is obtained for an STO PMOS device with a 2 μm effective gate length.

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Grazing-incidence X-ray diffraction of single GaAs nanowires at locations defined by focused ion beams

Journal of Applied Crystallography ◽

10.1107/s0021889813004226 ◽

2013 ◽

Vol 46 (4) ◽

pp. 887-892 ◽

Cited By ~ 4

Author(s):

Genziana Bussone ◽

Rüdiger Schott ◽

Andreas Biermanns ◽

Anton Davydok ◽

Dirk Reuter ◽

...

Keyword(s):

Gaas Substrate ◽

Lattice Spacing ◽

Molecular Beam ◽

Grazing Incidence ◽

Lattice Parameter ◽

Ion Beams ◽

Focused Ion Beams ◽

X Ray Diffraction ◽

X Ray ◽

Gaas Nanowires

Grazing-incidence X-ray diffraction measurements on single GaAs nanowires (NWs) grown on a (111)-oriented GaAs substrate by molecular beam epitaxy are reported. The positions of the NWs are intentionally determined by a direct implantation of Au with focused ion beams. This controlled arrangement in combination with a nanofocused X-ray beam allows the in-plane lattice parameter of single NWs to be probed, which is not possible for randomly grown NWs. Reciprocal space maps were collected at different heights along the NW to investigate the crystal structure. Simultaneously, substrate areas with different distances from the Au-implantation spots below the NWs were probed. Around the NWs, the data revealed a 0.4% decrease in the lattice spacing in the substrate compared with the expected unstrained value. This suggests the presence of a compressed region due to Au implantation.

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