A Molecular Dynamics Study of InGaAs Layers on GaAs Substrates

1994 ◽  
Vol 340 ◽  
Author(s):  
G J Moran ◽  
I Morrison ◽  
C C Matthai
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Elasticity Theory ◽  
Critical Thickness ◽  
Strain Relaxation ◽  
Thin Layers ◽  
Misfit Dislocations ◽  
Strain Relief ◽  
Gaas Substrates ◽  
Dynamics Simulations

ABSTRACTWe have performed molecular dynamics simulations of thin layers of InGaAs on GaAs substrates for different In concentrations to determine the critical thickness before strain relaxation occurs. We have considered both dislocation formation and islanding as possible mechanisms for strain relief. The results for the critical thickness for strain relief by misfit dislocations is slightly lower than that found using elasticity theory. For high In concentrations, facetted islands are found to be stable and are energetically favoured.

Strain Relief by Ion Beam Mixing. Molecular Dynamics Simulations Applied to Metallic Hetero-Structures

1993 ◽  
Vol 311 ◽  
Author(s):  
A.A. Mazzone
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Ion Beam ◽  
Low Energy ◽  
Ion Beam Mixing ◽  
Strain Relief ◽  
Dynamics Simulations

ABSTRACTThis work presents molecular dynamics simulations of low-energy (40-80 eV) ionbeam mixing of thin metallic hetero-structures. The results indicate that the propagation of the cascade may maintain or even restore crystallinity in disordered interfacial regions.

Strain relaxation in Si/Ge/Si nanoscale bars from molecular dynamics simulations

2009 ◽  
Vol 106 (3) ◽  
pp. 034304 ◽  
Author(s):  
Yumi Park ◽  
Hasan Metin Atkulga ◽  
Ananth Grama ◽  
Alejandro Strachan
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Strain Relaxation ◽  
Dynamics Simulations

scholarly journals Critical Thickness of Free-Standing Nanothin Films Made of Melted Polyethylene Chains via Molecular Dynamics

Polymers ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 3515
Author(s):  
José Antonio González-Mijangos ◽  
Enrique Lima ◽  
Roberto Guerra-González ◽  
Fernando Iguazú Ramírez-Zavaleta ◽  
José Luis Rivera
Keyword(s):  
Molecular Dynamics ◽  
Film Thickness ◽  
Molecular Dynamics Simulations ◽  
Critical Thickness ◽  
Mechanical Stability ◽  
Radius Of Gyration ◽  
Free Standing ◽  
Thermal Limit ◽  
Density Profiles ◽  
Dynamics Simulations

The mechanical stability of nanothin free-standing films made of melted polyethylene chains was predicted via molecular dynamics simulations in the range of 373.15–673.15 K. The predicted critical thickness, tc, increased with the square of the temperature, T, with additional chains needed as T increased. From T = 373.15 K up to the thermal limit of stability for polyethylene, tc values were in the range of nanothin thicknesses (3.42–5.63 nm), which approximately corresponds to 44–55 chains per 100 nm2. The density at the center of the layer and the interfacial properties studied (density profiles, interfacial thickness, and radius of gyration) showed independence from the film thickness at the same T. The polyethylene layer at its tc showed a lower melting T (<373.15 K) than bulk polyethylene.

Structural properties of GaAs/InGaAs/GaAs (001) and InGaAs/GaAs (001) heterostructures and correlation with electronic properties

1990 ◽  
Vol 48 (4) ◽  
pp. 602-603
Author(s):  
J.M. Bonar ◽  
R. Hull ◽  
R. Malik ◽  
R. Ryan ◽  
J.F. Walker
Keyword(s):  
Band Gap ◽  
Electronic Properties ◽  
Gaas Substrate ◽  
Critical Thickness ◽  
Lattice Mismatch ◽  
Band Offset ◽  
Misfit Dislocations ◽  
Gaas Substrates ◽  
Gaas Structure ◽  
Low X

In this study we have examined a series of strained heteropeitaxial GaAs/InGaAs/GaAs and InGaAs/GaAs structures, both on (001) GaAs substrates. These heterostructures are potentially very interesting from a device standpoint because of improved band gap properties (InAs has a much smaller band gap than GaAs so there is a large band offset at the InGaAs/GaAs interface), and because of the much higher mobility of InAs. However, there is a 7.2% lattice mismatch between InAs and GaAs, so an InxGa1-xAs layer in a GaAs structure with even relatively low x will have a large amount of strain, and misfit dislocations are expected to form above some critical thickness. We attempt here to correlate the effect of misfit dislocations on the electronic properties of this material.The samples we examined consisted of 200Å InxGa1-xAs layered in a hetero-junction bipolar transistor (HBT) structure (InxGa1-xAs on top of a (001) GaAs buffer, followed by more GaAs, then a layer of AlGaAs and a GaAs cap), and a series consisting of a 200Å layer of InxGa1-xAs on a (001) GaAs substrate.

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