Stimulated emission, laser oscillation, and its transient time relation in Zn 0.8 Cd 0.2 Se-ZnSe strained layer superlattice

1996 ◽  
Author(s):  
Zhuhong Zheng ◽  
Zhenping Guan ◽  
Xiwu Fan
Keyword(s):  
Stimulated Emission ◽  
Laser Oscillation ◽  
Transient Time ◽  
Strained Layer ◽  
Strained Layer Superlattice ◽  
Time Relation

Defect studies in strained-layer quantum well heterostructures

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 ◽  
Strained Layer Superlattice ◽  
Strained Layer Superlattices

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.

The limits of strain and lattice parameter measurements by CBED

1989 ◽  
Vol 47 ◽  
pp. 518-519
Author(s):  
Hamish L. Fraser
Keyword(s):  
Electron Beam ◽  
Mirror Symmetry ◽  
Local Symmetry ◽  
Lattice Parameter ◽  
Growth Direction ◽  
Surface Relaxation ◽  
Strained Layer ◽  
Axis Parallel ◽  
Local Lattice ◽  
Strained Layer Superlattice

The topic of strain and lattice parameter measurements using CBED is discussed by reference to several examples. In this paper, only one of these examples is referenced because of the limitation of length. In this technique, scattering in the higher order Laue zones is used to determine local lattice parameters. Work (e.g. 1) has concentrated on a model strained-layer superlattice, namely Si/Gex-Si1-x. In bulk samples, the strain is expected to be tetragonal in nature with the unique axis parallel to [100], the growth direction. When CBED patterns are recorded from the alloy epi-layers, the symmetries exhibited by the patterns are not tetragonal, but are in fact distorted from this to lower symmetries. The spatial variation of the distortion close to a strained-layer interface has been assessed. This is most readily noted by consideration of Fig. 1(a-c), which show enlargements of CBED patterns for various locations and compositions of Ge. Thus, Fig. 1(a) was obtained with the electron beam positioned in the center of a 5Ge epilayer and the distortion is consistent with an orthorhombic distortion. When the beam is situated at about 150 nm from the interface, the same part of the CBED pattern is shown in Fig. 1(b); clearly, the symmetry exhibited by the mirror planes in Fig. 1 is broken. Finally, when the electron beam is positioned in the center of a 10Ge epilayer, the CBED pattern yields the result shown in Fig. 1(c). In this case, the break in the mirror symmetry is independent of distance form the heterointerface, as might be expected from the increase in the mismatch between 5 and 10%Ge, i.e. 0.2 to 0.4%, respectively. From computer simulation, Fig.2, the apparent monocline distortion corresponding to the 5Ge epilayer is quantified as a100 = 0.5443 nm, a010 = 0.5429 nm and a001 = 0.5440 nm (all ± 0.0001 nm), and α = β = 90°, γ = 89.96 ± 0.02°. These local symmetry changes are most likely due to surface relaxation phenomena.

Optical and structural characteristics of InGaAs/GaAs strained-layer superlattice

1998 ◽  
Author(s):  
Mei Li ◽  
Xueqian Li ◽  
Xiaowei Song ◽  
Zhongjiu Ge ◽  
Xingde Zhang
Keyword(s):  
Structural Characteristics ◽  
Strained Layer ◽  
Strained Layer Superlattice

Growth of a novel InAs‐GaAs strained layer superlattice on InP

1985 ◽  
Vol 46 (6) ◽  
pp. 569-571 ◽  
Author(s):  
M. C. Tamargo ◽  
R. Hull ◽  
L. H. Greene ◽  
J. R. Hayes ◽  
A. Y. Cho
Keyword(s):  
Strained Layer ◽  
Strained Layer Superlattice

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

1987 ◽  
Vol 103 ◽  
Author(s):  
William C. Johnson
Keyword(s):  
Free Energy ◽  
Equilibrium State ◽  
Stable Equilibrium ◽  
Multiple Equilibrium ◽  
Equilibrium Thermodynamic ◽  
Relative Thickness ◽  
Two Phase ◽  
Strained Layer ◽  
Strained Layer Superlattice ◽  
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.

High Spin Polarization of Conduction Band Electrons in GaAs-GaAsP Strained Layer Superlattice Fabricated as a Spin-Polarized Electron Source

2004 ◽  
Vol 43 (6A) ◽  
pp. 3371-3375 ◽  
Author(s):  
Tetsuya Matsuyama ◽  
Hisaya Takikita ◽  
Hiromichi Horinaka ◽  
Kenji Wada ◽  
Tsutomu Nakanishi ◽  
...  
Keyword(s):  
Conduction Band ◽  
Spin Polarization ◽  
High Spin ◽  
Electron Source ◽  
Strained Layer ◽  
Spin Polarized ◽  
High Spin Polarization ◽  
Strained Layer Superlattice

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

1987 ◽  
Vol 91 ◽  
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 ◽  
Strained Layer Superlattice ◽  
Strained Layer Superlattices

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.

Sign in / Sign up

Export Citation Format

Share Document