Упругое взаимодействие квантовых дисков в гибридных QD/NW-структурах

The elastic interaction of quantum disks (QDs) in a nanowire (NW), i.e., in a hybrid QD/NW structure with sharp heterointerfaces, is considered for the first time. Within the framework of the defect micromechanics approach, the energy of QD pair interaction is established and it is demonstrated that for QDs with a lattice mismatch of the same sign, an attraction zone appears to each other, depending on the ratio of the axial size of the QD to the radius of the NW. The discovered effect should be taken into account when choosing the modes of formation of hybrid QD/NW structures and in models explaining their properties.

Download Full-text

Raman Characterization of Composition and Strain in Si1−xGex/Si Heterostructures

MRS Proceedings ◽

10.1557/proc-591-277 ◽

1999 ◽

Vol 591 ◽

Cited By ~ 1

Author(s):

Ran Liu ◽

B. Tillack ◽

P. Zaumseil

Keyword(s):

Lattice Mismatch ◽

Uniaxial Stress ◽

Longitudinal Optical ◽

Biaxial Stress ◽

Optical Phonon Mode ◽

Polarized Raman ◽

First Time ◽

Strain Frequency ◽

Raman Characterization

ABSTRACTHigh quality epitaxial Sil−xGex/Si (x = 0.09 to 0.27) samples were studied with polarized Raman scattering technique. The LO (longitudinal optical) -TO (transversal optical) phonon mode splitting due to the tetragonal strain imposed by the lattice mismatch between Sil−xGex and Si was observed for the first time in such structures. In contrast to the case of uniaxial stress, the biaxial stress induces a larger strain frequency shift for the LO mode than for the TO mode. The phonon strain shift coefficient for the LO mode was found to be 1010 cm−1, which is larger than most of the values reported in the literatures, and almost composition independent throughout the range of x≤0.27. We argue that the smaller LO strain shift coefficients indicate that the Sil−xGex films used in previous work were partially relaxed.

Download Full-text

Strain Relief in SrF2 Epitaxial Films on Si(111) Substrates

MRS Proceedings ◽

10.1557/proc-263-433 ◽

1992 ◽

Vol 263 ◽

Cited By ~ 2

Author(s):

Weidan Li ◽

Anthony P. Taylor ◽

Leo J. Schowalter

Keyword(s):

Film Thickness ◽

Lattice Mismatch ◽

Strained Layers ◽

Mbe Growth ◽

Molecular Beam Epitaxial ◽

Ion Channeling ◽

Large Lattice ◽

Large Lattice Mismatch ◽

Relationship Of ◽

First Time

ABSTRACTMolecular beam epitaxial (MBE) growth condition of SrF2 directly on Si(111) substrates has been optimized in terms of both Xmin and the surface morphology. Lattice distortion measurements were carried out with ion channeling along off-normal channeling directions in the strained layers grown at the optimal condition. The relationship of residual strain vs. film thickness for SrF2 on Si(111) was provided by the first time. The experimental data demonstrated a special thickness in this relation, at which the derivative of strain vs. film thickness changes its sign. This unique behavior was understood as the result of competition between the large lattice mismatch and the large thermal mismatch between SrF2 and Si.

Download Full-text

Epitaxial Growth of Ru and Pt on Pt(111) and Ru(0001), Respectively: A Combined AES and RHEED Study

Journal of Nanotechnology ◽

10.1155/2010/487193 ◽

2010 ◽

Vol 2010 ◽

pp. 1-12 ◽

Cited By ~ 2

Author(s):

M. S. Zei

Keyword(s):

Epitaxial Growth ◽

Room Temperature ◽

Lattice Mismatch ◽

High Energy ◽

Twin Plane ◽

Surface Strain ◽

High Energy Electron ◽

Direction Parallel ◽

Plane Normal ◽

First Time

The epitaxial growth of Pt and Ru deposits by spontaneous, as well as by dynamic, electrodeposition onto Ru(0001) and Pt(111), respectively, have been studied by reflection high energy electron diffraction (RHEED) and Auger electron spectroscopy (AES). For the Pt deposit on Ru(0001), at submonolayer range, it preferably grows compressed commensurate bilayer thick islands on Ru(0001). This is the first time that RHEED observation of the onset of Pt twinning occurs in ca. 2-3 layer thick islands on Ru at room temperature, at which the surface strain due to the 2.5% lattice mismatch of Pt and Ru remains intact. For multilayer thick islands (>6 ML) ordered reflection twins (diameter of 3 nm) develop and are embedded in a (111) matrix with an incoherent (11-2) twin plane normal to Ru(0001) and aligned with their [−110] direction parallel to the [11-20] Ru(0001) substrate direction. For the Ru deposit on Pt(111), at 0.2 ML a strained () monoatomic layer is formed due to the 2.5% lattice mismatch of Ru and Pt. Increasing the coverage up to 0.64, the second Ru layer is found to relieve the strain in the first layer, giving rise to dislocations and Ru relaxes to its bulk lattice constant. Multilayers of Ru (>1 ML) result in (0001) nanocluster formation aligned with its [11-20] direction parallel to the [−110] Pt(111) substrate direction.

Download Full-text

STRAIN RELAXATION IN SEMICONDUCTOR HETEROSTRUCTURES

Modern Physics Letters B ◽

10.1142/s0217984995000607 ◽

1995 ◽

Vol 09 (11n12) ◽

pp. 655-664

Author(s):

A. FISCHER ◽

H. KÜHNE

Keyword(s):

Lattice Mismatch ◽

Strain Relaxation ◽

Elastic Interaction ◽

Equilibrium Theory ◽

Semiconductor Heterostructures ◽

Misfit Dislocations ◽

Strain Relief ◽

New Approach ◽

Semiconductor Structures ◽

Theoretical Predictions

A brief review is presented for our new approach in equilibrium theory for strain relaxation in metastable heteroepitaxial semiconductor structures, one which includes the elastic interaction between straight misfit dislocations and the lattice mismatch accommodation by tetragonal distortion of the cubic lattice cells. This approach provides an equilibrium theory which correctly predicts critical strained layer thicknesses and completely describes the strain relief via plastic flow and the phenomenon of work hardening in lattice mismatched epilayers. Experimentally observed values of critical layer thickness and strain relief are discussed and compared with our theoretical predictions.

Download Full-text

Epitaxial BaF2-CaF2 Stacks on Si(111) and Si(100)

MRS Proceedings ◽

10.1557/proc-116-425 ◽

1988 ◽

Vol 116 ◽

Cited By ~ 5

Author(s):

S. Blunier ◽

H. Zogg ◽

H. Weibel

Keyword(s):

Free Energy ◽

Surface Free Energy ◽

Lattice Mismatch ◽

Lattice Orientation ◽

Stages Of Growth ◽

First Time ◽

Lattice Matched

AbstractStacks of non lattice matched epitaxial CaF2, SrF2 and BaF2 layers have been grown by MBE onto Si(lll), and, for the first time, onto Si(l00). On CaF2 covered Si(lll) surfaces, BaF2 grows in a 2—d way after formation of the first monolayers despite a lattice mismatch of 14%. On Si(l00), BaF2 grows with the same (100)—lattice orientation as the underlying substrateif at least a thin (=100 Å) intermediate CaF2 layer is deposited first. Growth is 3—d on (100)—surfaces because of the large (100)—surface free energy of the group IIa—fluorides. By applying in situ short anneal cyclesat the first stages of growth, the crystallographic quality increases for (111)— as well as for (100)—orientation.

Download Full-text

Strain Effects in Superlattices of Diluted Magnetic Semiconductor ZnTe/Zn1-xMnxTe

MRS Proceedings ◽

10.1557/proc-475-297 ◽

1997 ◽

Vol 475 ◽

Author(s):

Chenjia Chen ◽

Xi Chen ◽

Xiaoli Li ◽

Haitiao Li ◽

Xuezhong Wang ◽

...

Keyword(s):

Molecular Beam ◽

Heavy Hole ◽

Lattice Mismatch ◽

Diluted Magnetic Semiconductor ◽

Magnetic Semiconductor ◽

Heavy Hole Subband ◽

Resonant Raman ◽

Resonant Raman Scattering ◽

Diluted Magnetic ◽

First Time

ABSTRACTZnTe/Zn1-xMnxTe superlattices were grown on GaAs (001) substrates by molecular beam epitaxy. The multi-phonon processes including overtones and combinations of optical phonons have been studied by near resonant Raman scattering in the temperature range 13 K to 300 K. The strain arising from lattice mismatch gives rise to a shift in the optical-phonon frequencies. A two-phonon interface mode of superlattice has been observed and identified for the first time. Strain-induced red shifts of exciton energies related to transitions from the conduction subband to the light-hole and heavy-hole subband have been found by photoreflectance measurements. Experimental results agree well with the calculated strain-induced shift in superlattices.

Download Full-text

Alternative Magnesium Calcium Oxide Gate Dielectric for Silicon Carbide MOS Application

MRS Proceedings ◽

10.1557/proc-0911-b14-03 ◽

2006 ◽

Vol 911 ◽

Cited By ~ 3

Author(s):

Danielle Stodilka ◽

A. P. Gerger ◽

M. Hlad ◽

P. Kumar ◽

B. P. Gila ◽

...

Keyword(s):

Low Temperature ◽

Gate Dielectric ◽

Lattice Mismatch ◽

Gate Dielectrics ◽

Electrical Breakdown ◽

Gas Source ◽

Gas Source Mbe ◽

First Time ◽

Uv Ozone ◽

Density Of Interface States

AbstractFilms of MgO and MgCaO ternaries were grown at low temperature as dielectrics on 6H-SiC by gas-source MBE. MgO grown at 300 and 400°C revealed crystallites textured toward the (111) orientation on SiC (0001). A solid-solution Mg.75Ca.25O ternary was grown having a minimal lattice mismatch and low root mean square (RMS) roughness of 0.5 nm. SiC pretreatments in UV-ozone reduced carbon contaminants on the surface of SiC, but resulted in the increase of fixed oxide charge in the oxide/SiC interface. Electrical breakdown fields >3.5 MV cm-1 and low density of interface states on the order of 1011 cm-2eV-1 were achieved for a Mg.75Ca.25O ternary grown at 300°C. These oxides are presented for the first time as low temperature alternatives to SiO2 gate dielectrics for SiC MOS applications.

Download Full-text

Van Der Waals Epitaxy of Transition Metal Dichalcogenides Using Metal Organic Precursors (Movdwe)

MRS Proceedings ◽

10.1557/proc-441-591 ◽

1996 ◽

Vol 441 ◽

Cited By ~ 3

Author(s):

S. Tiefenbacher ◽

C. Pettenkofer ◽

W. Jaegermann

Keyword(s):

Transition Metal ◽

Lattice Mismatch ◽

Van Der Waals ◽

Transition Metal Dichalcogenides ◽

Intensity Variation ◽

High Crystalline Quality ◽

Metal Dichalcogenides ◽

Metal Organic ◽

Organic Precursors ◽

First Time

AbstractEpitaxial WS2 films have been grown on MoTe2 (0001) van der Waals faces using W(CO)6 and SnS2 as precursors. Despite a lattice mismatch of 10.3 % the film shows high crystalline quality. The interface is atomically abrupt and shows no interface dangling bonds as deduced from photoemission results (XPS, UPS). The growing overlayer nucleates on the flat (0001) terraces and not on steps as suggested from STM-measurements. For thin epilayers Moiré superstructures in LEED have been measured for the first time in semiconductor heteroepitaxy. From the intensity variation of the LEED spots with energy a corrugation of the overlayer film can be deduced. Based on these results a mechanism of van der Waals epitaxy is suggested.

Download Full-text

PHOTOLUMINESCENCE OF BIEXCITON IN ZnO EPITAXIAL THIN FILMS

International Journal of Modern Physics B ◽

10.1142/s0217979201008263 ◽

2001 ◽

Vol 15 (28n30) ◽

pp. 3611-3614 ◽

Cited By ~ 1

Author(s):

KENSUKE MIYAJIMA ◽

AISHI YAMAMOTO ◽

TAKENARI GOTO ◽

HANG JU KO ◽

TAKAFUMI YAO

Keyword(s):

Thin Films ◽

Buffer Layer ◽

Sapphire Substrate ◽

Lattice Mismatch ◽

Zno Films ◽

Epitaxial Thin Films ◽

Excitation Spectra ◽

Temporal Dependence ◽

First Time ◽

Gan Buffer Layer

We have measured excitation dependence of photoluminescence (PL) spectra, excitation spectra of PL (PLE) and temporal dependence of the PL intensity in ZnO epitaxial thin films. The ZnO films were grown on a sapphire substrate with a GaN buffer layer to reduce a lattice mismatch. We succeeded in observing a PL due to biexciton for the first time in ZnO epitaxial thin films.

Download Full-text

Metalorganic Magnetron Sputter Deposition of In1-xGax on (100)GaAs

MRS Proceedings ◽

10.1557/proc-160-427 ◽

1989 ◽

Vol 160 ◽

Author(s):

R. Rousina ◽

J.B. Webb ◽

J.P. Noad

Keyword(s):

Lattice Mismatch ◽

Sputter Deposition ◽

Temperature Growth ◽

Large Lattice ◽

Epitaxial Deposition ◽

Magnetron Sputter Deposition ◽

Large Lattice Mismatch ◽

Magnetron Sputter ◽

First Time ◽

Constant Growth

AbstractThis work reports for the first time, the epitaxial deposition of ln1-xGaxSb on (100)GaAs by Metalorganic Magnetron Sputtering. High quality films could be deposited on GaAs over the entire compositional range despite the large lattice mismatch between the film and substrate (14.6% for InSb and 7.8% for GaSb). The composition of the layers was found to be directly related to the trimethylgallium and trimethylindium fluxes at constant growth temperature. Growth rates of 1 µm/hr for the GaSb and 3 µm/hr for the InSb were observed.

Download Full-text