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Microstructure of non-polar GaN on LiGaO2 grown by plasma-assisted MBE.

Shih CH, Huang TH, Schuber R, Chen YL, Chang L, Lo I, Chou MM, Schaadt DM - Nanoscale Res Lett (2011)

Bottom Line: The already reported epi-taxial relationship and for M -plane GaN is confirmed.For the M -plane sample, the density of threading dislocations is around 1 × 1011 cm-2 and the stacking fault density amounts to approximately 2 × 105 cm-1.In the A-plane sample, a threading dislocation density in the same order was found, while the stacking fault density is much lower than in the M -plane sample.

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Affiliation: Institute for Applied Physics/DFG-Center for Functional Nanostructures (CFN), Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany. ralf.schuber@kit.edu.

ABSTRACT
We have investigated the structure of non-polar GaN, both on the M - and A-plane, grown on LiGaO2 by plasma-assisted molecular beam epitaxy. The epitaxial relationship and the microstructure of the GaN films are investigated by transmission electron microscopy (TEM). The already reported epi-taxial relationship and for M -plane GaN is confirmed. The main defects are threading dislocations and stacking faults in both samples. For the M -plane sample, the density of threading dislocations is around 1 × 1011 cm-2 and the stacking fault density amounts to approximately 2 × 105 cm-1. In the A-plane sample, a threading dislocation density in the same order was found, while the stacking fault density is much lower than in the M -plane sample.

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TEM data of the A-plane sample, with viewing direction . (a) Diffraction pattern of the GaN film of the A-plane GaN sample. (b) and (c) show bright field images of the same sample taken in the two beam conditions with  = (0002) and , respectively.
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Figure 5: TEM data of the A-plane sample, with viewing direction . (a) Diffraction pattern of the GaN film of the A-plane GaN sample. (b) and (c) show bright field images of the same sample taken in the two beam conditions with = (0002) and , respectively.

Mentions: Figure 5b and 5c shows bright field images of the A-plane GaN sample cut perpendicular to the direction taken in the two beam condition with = (0002) and , respectively. Damage to the substrate by the electron beam is again seen. Threading dislocations as well as stacking faults are visible. Slightly more dislocations appear in the image with = (0002) indicating that there are more pure screw threading dislocations than edge dislocations. In comparison to the M -plane GaN sample, much fewer stacking faults are present in the A-plane film. This observation is also confirmed by the missing streaks in the diffraction pattern, shown in Figure 5a. This means that the stacking fault density is lower than ~105 cm-1, and therefore lower than values reported previously, e.g. for A-plane GaN on R-plane Sapphire, 3.83 × 105 cm-1 [7].


Microstructure of non-polar GaN on LiGaO2 grown by plasma-assisted MBE.

Shih CH, Huang TH, Schuber R, Chen YL, Chang L, Lo I, Chou MM, Schaadt DM - Nanoscale Res Lett (2011)

TEM data of the A-plane sample, with viewing direction . (a) Diffraction pattern of the GaN film of the A-plane GaN sample. (b) and (c) show bright field images of the same sample taken in the two beam conditions with  = (0002) and , respectively.
© Copyright Policy - open-access
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3211842&req=5

Figure 5: TEM data of the A-plane sample, with viewing direction . (a) Diffraction pattern of the GaN film of the A-plane GaN sample. (b) and (c) show bright field images of the same sample taken in the two beam conditions with = (0002) and , respectively.
Mentions: Figure 5b and 5c shows bright field images of the A-plane GaN sample cut perpendicular to the direction taken in the two beam condition with = (0002) and , respectively. Damage to the substrate by the electron beam is again seen. Threading dislocations as well as stacking faults are visible. Slightly more dislocations appear in the image with = (0002) indicating that there are more pure screw threading dislocations than edge dislocations. In comparison to the M -plane GaN sample, much fewer stacking faults are present in the A-plane film. This observation is also confirmed by the missing streaks in the diffraction pattern, shown in Figure 5a. This means that the stacking fault density is lower than ~105 cm-1, and therefore lower than values reported previously, e.g. for A-plane GaN on R-plane Sapphire, 3.83 × 105 cm-1 [7].

Bottom Line: The already reported epi-taxial relationship and for M -plane GaN is confirmed.For the M -plane sample, the density of threading dislocations is around 1 × 1011 cm-2 and the stacking fault density amounts to approximately 2 × 105 cm-1.In the A-plane sample, a threading dislocation density in the same order was found, while the stacking fault density is much lower than in the M -plane sample.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute for Applied Physics/DFG-Center for Functional Nanostructures (CFN), Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany. ralf.schuber@kit.edu.

ABSTRACT
We have investigated the structure of non-polar GaN, both on the M - and A-plane, grown on LiGaO2 by plasma-assisted molecular beam epitaxy. The epitaxial relationship and the microstructure of the GaN films are investigated by transmission electron microscopy (TEM). The already reported epi-taxial relationship and for M -plane GaN is confirmed. The main defects are threading dislocations and stacking faults in both samples. For the M -plane sample, the density of threading dislocations is around 1 × 1011 cm-2 and the stacking fault density amounts to approximately 2 × 105 cm-1. In the A-plane sample, a threading dislocation density in the same order was found, while the stacking fault density is much lower than in the M -plane sample.

No MeSH data available.


Related in: MedlinePlus