On the Existence of Multiple Equilibrium States in Strained-Layer Superlattices

ABSTRACTUsing recent results from the thermodynamics of stressed solids, two-phase coexistence in a simple binary strained-layer superlattice is examined. We show that for a given temperature and overall composition of the superlattice, there can exist more than one linearly stable, equilibrium thermodynamic state. That is, there may exist several combinations of relative thickness of the phases and corresponding phase compositions that minimize the free energy of the system. The equilibrium state observed experimentally can, therefore, be influenced by the processing path.

Defect Reduction in GaAs Epilayers on Si Substrates Using Strained Layer Superlattices

MRS Proceedings ◽

10.1557/proc-91-99 ◽

1987 ◽

Vol 91 ◽

Cited By ~ 9

Author(s):

N. El-Masry ◽

N. Hamaguchi ◽

J.C.L. Tarn ◽

N. Karam ◽

T.P. Humphreys ◽

...

Keyword(s):

Thermal Annealing ◽

Rapid Thermal Annealing ◽

Buffer Layers ◽

Threading Dislocations ◽

Defect Reduction ◽

Strained Layer ◽

Si Substrates ◽

Density Of Dislocations ◽

ABSTRACTInxGa11-xAs-GaAsl-yPy strained layer superlattice buffer layers have been used to reduce threading dislocations in GaAs grown on Si substrates. However, for an initially high density of dislocations, the strained layer superlattice is not an effective filtering system. Consequently, the emergence of dislocations from the SLS propagate upwards into the GaAs epilayer. However, by employing thermal annealing or rapid thermal annealing, the number of dislocation impinging on the SLS can be significantly reduced. Indeed, this treatment greatly enhances the efficiency and usefulness of the SLS in reducing the number of threading dislocations.

The Growth of InAsSb/InGaAs Strained-Layer Superlattices by Metal-Organic Chemical Vapor Deposition

MRS Proceedings ◽

10.1557/proc-325-493 ◽

1993 ◽

Vol 325 ◽

Cited By ~ 3

Author(s):

R. M. Biefeld ◽

K. C. Baucom ◽

S. R. Kurtz ◽

D. M. Follstaedt

Keyword(s):

Chemical Vapor Deposition ◽

Thermodynamic Model ◽

Vapor Deposition ◽

Chemical Vapor ◽

Organic Chemical ◽

Strained Layer ◽

Metal Organic ◽

Strained Layer Superlattices ◽

Organic Chemical Vapor Deposition

AbstractWe have grown InAsl-xSbx/Inl-yGayAs strained-layer superlattice (SLS) semiconductors lattice matched to InAs using a variety of conditions by metal-organic chemical vapor deposition. The V/III ratio was varied from 2.5 to 10 at a temperature of 475 °C, at pressures of 200 to 660 torr and growth rates of 3 - 5 A/s and layer thicknesses ranging from 55 to 152 Å. The composition of the InAsSb ternary can be predicted from the input gas molar flow rates using a thermodynamic model. At lower temperatures, the thermodynamic model must be modified to take account of the incomplete decomposition of arsine and trimethylantimony. Diodes have been prepared using Zn as the p-type dopant and undoped SLS as the n-type material. The diode was found to emit at 3.56 μm. These layers have been characterized by optical microscopy, SIMS, x-ray diffraction, and transmission electron diffraction. The optical properties of these SLS's were determined by infrared photoluminescence and absorption measurements.

Raman Study of Strain and Confinement Effects in Si/Ge Strained Layer Superlattices Under Hydrostatic Pressure

MRS Proceedings ◽

10.1557/proc-220-333 ◽

1991 ◽

Vol 220 ◽

Author(s):

Zhifeng Sui ◽

Irving P. Herman ◽

Joze Bevk

Keyword(s):

Hydrostatic Pressure ◽

Raman Scattering ◽

Optical Phonon ◽

Phonon Frequency ◽

Optical Phonons ◽

Biaxial Strain ◽

Strained Layer ◽

Raman Study ◽

ABSTRACTThe effects of strain and confinement on optical phonons in a Si12Ge4 strained layer superlattice grown by MBE on c-Si (001) were studied as a function of hydrostatic pressure (T = 295 K) using Raman scattering. The change of phonon frequency with pressure, dω/dP, for the principal quasi-confined LO mode in the Ge layers is found to be significantly smaller than that for bulk crystalline Ge because the magnitude of biaxial strain decreases in the Ge layers with added pressure and because the Grüneisen parameter of the confined mode is smaller than that of the Γ-point optical phonon. More generally, it is noted that the magnitude of biaxial strain in many strained layer superlattices initially decreases with the application of hydrostatic pressure, making the structures more stable.

Optical Absorption Probability for the Zone-Folding Induced Quasi-Direct Gap in Ge(x)Si(1−x)/Si Strained Layer Superlattices

MRS Proceedings ◽

10.1557/proc-56-365 ◽

1985 ◽

Vol 56 ◽

Cited By ~ 12

Author(s):

S. A. Jackson ◽

R. People

Keyword(s):

Transition Probability ◽

Optical Devices ◽

Optical Transitions ◽

Absorption Probability ◽

Strained Layer ◽

Optical Gap ◽

Indirect Band Gap ◽

Strained Layer Superlattices ◽

Zone Folding

AbstractUsing a realistic zone-folding scheme for a Ge(x)Si(1−x)/Si strained layer superlattice having a Si-like conduction band structure (i.e ≲85% Ge) we calculate the transition probability for the zone-folding induced direct optical gap and compare it with the indirect band gap absorption probability. The results suggest that such zone-folding induced direct optical transitions are promising for optical devices made from Ge(x)Si(1−x)/Si strained layer superlattices and like structures, provided they are fabricated in such a way that the appropriate zone-folding occurs.

Defect studies in strained-layer quantum well heterostructures

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100074471 ◽

1983 ◽

Vol 41 ◽

pp. 120-121

Author(s):

J.M. Brown ◽

M.E. Mochel ◽

N. Holonyak ◽

M.D. Camras ◽

M.J. Ludowise ◽

...

Keyword(s):

Electron Microscope ◽

Epitaxial Growth ◽

Vapor Phase ◽

Microscope Study ◽

Electron Microscope Study ◽

Stimulated Emission ◽

High Excitation ◽

Strained Layer ◽

The epitaxial growth of mismatched or strained III-V layers was shown to be viable as early as 1960. Osbourn et al suggested that strained layer GaP-GaAs1-xPx superlattices grown by organo-metal1ic vapor phase epitaxy (OMVPE) could be used to fold the Brillouin zone and make indirect-crystal direct. More recently, it has been shown that a strained-layer superlattice can be grown free enough of defects at heterointerfaces to make possible stimulated emission. This has been demonstrated on OMVPE GaAs1-xPx-GaAs (x=0.25) and GaAs-InxGa1-xAs (x=0.2) strained layer superlattices which have been operatedas photopuraped continuous (cw) 300K lasers but which at high excitation levels (> 103Acm-2) prove to be unstable. This paper presents the results of an electron microscope study of the defects produced in a GaAs-InxGa1-xAs strained superlattice as a result of high excitation levels of operation.

Growth of (GaAs)1−x (Si2)x Metastable Alloys using Migration-Enhanced Epitaxy

MRS Proceedings ◽

10.1557/proc-222-151 ◽

1991 ◽

Vol 222 ◽

Cited By ~ 1

Author(s):

T. Sudersena Rao ◽

Y. Horikoshi

Keyword(s):

Buffer Layers ◽

Double Crystal ◽

Cross Sectional ◽

Strained Layer ◽

Si Substrates ◽

Migration Enhanced Epitaxy ◽

Metastable Alloys ◽

Si Content ◽

ABSTRACTEpitaxial (GaAs)1−x (Si2)x metastable alloys have been grown on GaAs (100) substrates using Migration-Enhanced Epitaxy in the composition range of 0<x<0.25. The lattice constant a0 of the alloys was found to decrease with increasing Si content from 0.56543nm at x=0 to 0.5601nm at x=0.25. Double-crystal x-ray diffraction rocking curve measurements and cross-sectional transmission electron microscopy studies made on a 10 period (GaAs)1−x(Si2)x/GaAs strained layer superlattice indicated sharp and abrupt interfaces. High crystalline quality GaAs has been grown on Si substrates using (GaAs)0.80(Si2)0.20/GaAs strained layer superlattices as buffer layers.

Effect Of AlGaN/GaN Strained Layer Superlattice Period On InGaN MQW Laser Diodes

MRS Internet Journal of Nitride Semiconductor Research ◽

10.1557/s1092578300004026 ◽

2000 ◽

Vol 5 (S1) ◽

pp. 14-19 ◽

Cited By ~ 1

Author(s):

Monica Hansen ◽

Amber C. Abare ◽

Peter Kozodoy ◽

Thomas M. Katona ◽

Michael D. Craven ◽

...

Keyword(s):

Hole Concentration ◽

Laser Diodes ◽

Chemical Vapor ◽

Threshold Current ◽

Threshold Current Density ◽

Strained Layer ◽

Strained Layer Superlattices ◽

Cladding Layers ◽

Superlattice Period

AlGaN/GaN strained layer superlattices have been employed in the cladding layers of InGaN multi-quantum well laser diodes grown by metalorganic chemical vapor deposition (MOCVD). Superlattices have been investigated for strain relief of the cladding layer, as well as an enhanced hole concentration, which is more than ten times the value obtained for bulk AlGaN films. Laser diodes with strained layer superlattices as cladding layers were shown to have superior structural and electrical properties compared to laser diodes with bulk AlGaN cladding layers. As the period of the strained layer superlattices is decreased, the threshold voltage, as well as the threshold current density, is decreased. The resistance to vertical conduction through p-type superlattices with increasing superlattice period is not offset by the increase in hole concentration for increasing superlattice spacing, resulting in higher voltages.

Resonance between Channeled Particle Wavelengths and Periodicity of Strained-Layer Superlattices

MRS Proceedings ◽

10.1557/proc-25-483 ◽

1983 ◽

Vol 25 ◽

Author(s):

W. K. Chu ◽

S. T. Picraux ◽

R. M. Biefeld ◽

G. C. Osbourn ◽

J. A. Ellison

Keyword(s):

Resonance Effect ◽

Incident Beam ◽

Strained Layer ◽

Phase Rotation ◽

Half Wavelength ◽

Channeled Particle ◽

Simple Phase ◽

Incident Beam Energy ◽

ABSTRACTRecent studies of the resonance effect between the wavelength of planar channeled ions and the periodicity of strained-layer superlattices are summarized for MeV 4He ions backscattering from GaAsxP1-X/GaP superlattices. When the incident beam energy is adjusted so the half-wavelength matches the thickness of the layers, a catastrophic dechanneling effect is observed. A simple phase rotation analysis has been developed to calculate the dechanneling in each layer and good agreement is obtained with the observed dechanneling per interface. This resonance effect is used to measure the amount of strain in the GaAsxP1-x/GaP strained-layer superlattice.

Deformation of Small Volumes of Material Studied Using Strained-Layer Superlattice Structures

MRS Proceedings ◽

10.1557/proc-778-u6.3 ◽

2003 ◽

Vol 778 ◽

Cited By ~ 2

Author(s):

K.M.Y. P'ng ◽

A.J. Bushby ◽

D.J. Dunstan

Keyword(s):

Yield Stress ◽

Finite Volume ◽

Internal Stresses ◽

Strained Layer ◽

Initial Yield Stress ◽

Semiconductor Superlattice ◽

Initial Yield ◽

Superlattice Structures ◽

AbstractMechanical studies of semiconductor superlattices have shown that the onset of plastic deformation under an inhomogeneous stress is a process that takes place simultaneously across a finite volume of the order of a micron across. The ability to incorporate known internal stresses, and to vary the stress and thickness of individual layers in a semiconductor superlattice, is a very powerful tool, opening up new possibilities for investigations that cannot be achieved by varying external stresses on a specimen that is sensibly homogeneous. In this way, from the initial yield stress of single-crystal strained-layer superlattices under indentation, we demonstrated a new criterion, of which the key feature is that it is to be averaged over a finite volume. Here we show that designing samples with individual layers in bands to form low yield-stress material within the structure can give information about the size and position of the initial yield volume.

Determination of atomic vacancies in InAs/GaSb strained-layer superlattices by atomic strain

IUCrJ ◽

10.1107/s2052252517016219 ◽

2018 ◽

Vol 5 (1) ◽

pp. 67-72 ◽

Cited By ~ 4

Author(s):

Honggyu Kim ◽

Yifei Meng ◽

Ji-Hwan Kwon ◽

Jean-Luc Rouviére ◽

Jian Min Zuo

Keyword(s):

Vacancy Defect ◽

Strain Mapping ◽

Vacancy Defects ◽

Strained Layer ◽

Anion Vacancies ◽

Local Lattice ◽

Cation And Anion Vacancies ◽

Complex Crystals ◽

Determining vacancy in complex crystals or nanostructures represents an outstanding crystallographic problem that has a large impact on technology, especially for semiconductors, where vacancies introduce defect levels and modify the electronic structure. However, vacancy is hard to locate and its structure is difficult to probe experimentally. Reported here are atomic vacancies in the InAs/GaSb strained-layer superlattice (SLS) determined by atomic-resolution strain mapping at picometre precision. It is shown that cation and anion vacancies in the InAs/GaSb SLS give rise to local lattice relaxations, especially the nearest atoms, which can be detected using a statistical method and confirmed by simulation. The ability to map vacancy defect-induced strain and identify its location represents significant progress in the study of vacancy defects in compound semiconductors.