Strain relaxation behavior of the InGaN/GaN multiple quantum wells observed by transmission electron microscopy

The relaxation properties of GH4169 alloy were studied contrastively at temperatures ranging from 600 oC to 700 °C and initial stress ranging from 550 MPa to 850 MPa. The relationship between the microstructure and relaxation behavior was evaluated using transmission electron microscopy techniques. It was found that the relaxation limit and relaxation stability of the alloy decreased obviously with the increase of temperature. Further investigations show that the relaxation behavior is mainly depend on both precipitate characteristics and its interaction with dislocations. The alloy with higher strength lever has more excellent stress relaxation stability, because of the inhibition of a large number subgrains on dislocations motion.

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Transmission electron microscopy of misfit dislocation and strain relaxation in lattice mismatched III-V heterostructures versus substrate surface treatment

MRS Proceedings ◽

10.1557/opl.2011.841 ◽

2011 ◽

Vol 1324 ◽

Author(s):

Y. Wang ◽

P. Ruterana ◽

L. Desplanque ◽

S. El Kazzi ◽

X. Wallart

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Surface Treatment ◽

Substrate Surface ◽

Strain Relaxation ◽

Dislocation Core ◽

Misfit Dislocations ◽

Heteroepitaxial Growth ◽

Transmission Electron ◽

Growth Initiation

ABSTRACTHigh resolution transmission electron microscopy in combination with geometric phase analysis is used to investigate the interface misfit dislocations, strain relaxation, and dislocation core behavior versus the surface treatment of the GaAs for the heteroepitaxial growth of GaSb. It is pointed out that Sb-rich growth initiation promotes the formation of a high quality network of Lomer misfit dislocations that are more efficient for strain relaxation.

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Mechanisms of misfit strain relaxation in epitaxially grown BLT (Bi4-xLaxTi3O12, x = 0.75) thin films

MRS Proceedings ◽

10.1557/proc-779-w5.23 ◽

2003 ◽

Vol 779 ◽

Author(s):

Hyung Seok Kim ◽

Sang Ho Oh ◽

Ju Hyung Suh ◽

Chan Gyung Park

Keyword(s):

Electron Microscopy ◽

Thin Films ◽

Transmission Electron Microscopy ◽

Strain Relaxation ◽

Lattice Misfit ◽

Misfit Strain ◽

Misfit Dislocations ◽

Transmission Electron ◽

Means Of Transmission ◽

20 Nm

AbstractMechanisms of misfit strain relaxation in epitaxially grown Bi4-xLaxTi3O12 (BLT) thin films deposited on SrTiO3 (STO) and LaAlO3 (LAO) substrates have been investigated by means of transmission electron microscopy (TEM). The misfit strain of 20 nm thick BLT films grown on STO substrate was relaxed by forming misfit dislocations at the interface. However, cracks were observed in 100 nm thick BLT films grown on the same STO. It was confirmed that cracks were formed because of high misfit strain accumulated with increasing the thickness of BLT, that was not sufficiently relaxed by misfit dislocations. In the case of the BLT film grown on LAO substrate, the magnitude of lattice misfit between BLT and LAO was very small (~1/10) in comparison with the case of the BLT grown on STO. The relatively small misfit strain formed in layered structure of the BLT films on LAO, therefore, was easily relaxed by distorting the film, rather than forming misfit dislocations or cracks, resulting in misorientation regions in the BLT film.

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