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Structural Analysis of Highly Relaxed GaSb Grown on GaSb Substrates with Periodic Interfacial Array of 90° Misfit Dislocations

Jallipalli, A. and Balakrishnan, G. and Huang, S. H. and Rotter, T. J. and Nunna, K. and Liang, B. L. and Dawson, L. R. and Huffaker, D. L. (2009) Structural Analysis of Highly Relaxed GaSb Grown on GaSb Substrates with Periodic Interfacial Array of 90° Misfit Dislocations. Nanoscale Research Letters, 4 (12). pp. 1458-1462.

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Abstract

We report structural analysis of completely relaxed GaAS epitaxial layers deposited monolithically on GaAs substrates using interfacial misfit (IMF) array growth mode. Unlike the traditional tetragonal distortion approach, strain due to the lattice mismatch is spontaneously relieved at the heterointerface in this growth. The complete and instantaneous strain relief at the GaSb/GaAs interface is achieved by the formation of a two-dimensional Lomer dislocation network comprising of pure-edge (90°) dislocations along both [110] and [1-10]. In the present analysis, structural properties of GaSb deposited using both IMF and non-IMF growths are compared. Moire fringe patterns along with X-ray diffraction measure the long-range uniformity and strain relaxation of the IMF samples. The proof for the existence of the IMF array and low threading dislocation density is provided with the help of transmission electron micrographs for the GaSb epitaxial layer. Our results indicate that the IMF-grown GaSb is completely (98.5%) relaxed with very low density of threading dislocations (105 cm−2), while GaSb deposited using non-IMF growth is compressively strained and has a higher average density of threading dislocations (>109 cm−2).

Item Type:Article
Subjects:Material Science > Nanochemistry
ID Code:8032
Deposited By:CSMNT
Deposited On:09 Aug 2010 15:22
Last Modified:18 Aug 2010 13:50

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