Rotational twins in heteroepitaxial CuInSe{sub 2} layers on Si(111)
- Arbeitsgemeinschaft fuer industrielle Forschung (AFIF) at Swiss Federal Institute of Technology, ETH-Trakt Technopark, Pfingstweidstrasse 30, 8005 Zuerich (Switzerland)
- ETH Zuerich, Institut fuer Angewandte Physik, 8093 Zuerich (Switzerland)
The microstructure of (112) oriented CuInSe{sub 2} heteroepitaxial layers grown with molecular beam epitaxy on (111) oriented Si wafers was investigated by transmission electron microscopy. Experimental and calculated diffraction patterns of different zone axes were compared. Extra spots are caused by rotational twins on (112) growth planes. Six twin variants rotated by {plus_minus}120{degree}, {plus_minus}60{degree} and 180{degree} about the [221] axis were identified in the layers. The tetragonal chalcopyrite structure of CuInSe{sub 2}, the crystal symmetry of the substrate and variations of the growth conditions during the growth are responsible for the formation of these rotational twins. Coherent twin boundaries as well as partly coherent boundaries of twin variants rotated by {plus_minus}60{degree} and 180{degree} were imaged by high resolution transmission electron microscopy. The boundaries can be formed by inserting partial dislocations with Burgers vectors {ital a}/6{l_angle}11{bar 1}{r_angle} into the CuInSe{sub 2} structure. This suggests that the annealing of the samples induces the annihilation of these partial dislocations and consequently reduces the density of twins in the CuInSe{sub 2} layers. {copyright} {ital 1997 American Institute of Physics.}
- OSTI ID:
- 496652
- Journal Information:
- Journal of Applied Physics, Vol. 81, Issue 9; Other Information: PBD: May 1997
- Country of Publication:
- United States
- Language:
- English
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