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Filtering of Defects in Semipolar (11-22) GaN Using 2-Steps Lateral Epitaxial Overgrowth.

Kriouche N, Leroux M, Vennéguès P, Nemoz M, Nataf G, de Mierry P - Nanoscale Res Lett (2010)

Bottom Line: Good-quality (11-22) semipolar GaN sample was obtained using epitaxial lateral overgrowth.The growth conditions were chosen to enhance the growth rate along the [0001] inclined direction.Thus, the coalescence boundaries stop the propagation of basal stacking faults.

View Article: PubMed Central - HTML - PubMed

Affiliation: Centre de Recherche sur l'Hétéroépitaxie et ses Applications CRHEA-CNRS, Rue Bernard Grégory, Sophia Antipolis, 06560 Valbonne, France.

ABSTRACT
Good-quality (11-22) semipolar GaN sample was obtained using epitaxial lateral overgrowth. The growth conditions were chosen to enhance the growth rate along the [0001] inclined direction. Thus, the coalescence boundaries stop the propagation of basal stacking faults. The faults filtering and the improvement of the crystalline quality were attested by transmission electron microscopy and low temperature photoluminescence. The temperature dependence of the luminescence polarization under normal incidence was also studied.

No MeSH data available.


Related in: MedlinePlus

Dark field TEM images of the coalescence boundary taken near the [2−1−10] GaN zone axis with diffraction vectors along [1–100] (a) and in the c-plane (b)
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Figure 2: Dark field TEM images of the coalescence boundary taken near the [2−1−10] GaN zone axis with diffraction vectors along [1–100] (a) and in the c-plane (b)

Mentions: Figure 2a, 2b is the cross-sectional TEM images of the coalescence boundaries along the [2−1−10] zone axis. This orientation is inclined by 30° from the in-plane [1–100] orientation and allows observing the stacking faults. BSFs are observable only on the <1–100> dark field image (a) and are out of contrast in the (0002) dark field (b). On the other hand, PDs are observable on both images. Few BSFs are present on the—c-wings but these faults do not affect the final quality of the film because they are stopped by the adjacent crystal. The dotted arrows show the coalescence boundary, the upper left side of these images corresponding to a +c-laterally grown wing and the lower right side to a seed crystal. No faults are present above the coalescence boundary, neither PDs nor BSFs. These observations show that the overgrowth of a-facets by +c-laterally growing wings is a very efficient mechanism to avoid the propagation of BSFs and related defects to the surface of the coalesced films.


Filtering of Defects in Semipolar (11-22) GaN Using 2-Steps Lateral Epitaxial Overgrowth.

Kriouche N, Leroux M, Vennéguès P, Nemoz M, Nataf G, de Mierry P - Nanoscale Res Lett (2010)

Dark field TEM images of the coalescence boundary taken near the [2−1−10] GaN zone axis with diffraction vectors along [1–100] (a) and in the c-plane (b)
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2991163&req=5

Figure 2: Dark field TEM images of the coalescence boundary taken near the [2−1−10] GaN zone axis with diffraction vectors along [1–100] (a) and in the c-plane (b)
Mentions: Figure 2a, 2b is the cross-sectional TEM images of the coalescence boundaries along the [2−1−10] zone axis. This orientation is inclined by 30° from the in-plane [1–100] orientation and allows observing the stacking faults. BSFs are observable only on the <1–100> dark field image (a) and are out of contrast in the (0002) dark field (b). On the other hand, PDs are observable on both images. Few BSFs are present on the—c-wings but these faults do not affect the final quality of the film because they are stopped by the adjacent crystal. The dotted arrows show the coalescence boundary, the upper left side of these images corresponding to a +c-laterally grown wing and the lower right side to a seed crystal. No faults are present above the coalescence boundary, neither PDs nor BSFs. These observations show that the overgrowth of a-facets by +c-laterally growing wings is a very efficient mechanism to avoid the propagation of BSFs and related defects to the surface of the coalesced films.

Bottom Line: Good-quality (11-22) semipolar GaN sample was obtained using epitaxial lateral overgrowth.The growth conditions were chosen to enhance the growth rate along the [0001] inclined direction.Thus, the coalescence boundaries stop the propagation of basal stacking faults.

View Article: PubMed Central - HTML - PubMed

Affiliation: Centre de Recherche sur l'Hétéroépitaxie et ses Applications CRHEA-CNRS, Rue Bernard Grégory, Sophia Antipolis, 06560 Valbonne, France.

ABSTRACT
Good-quality (11-22) semipolar GaN sample was obtained using epitaxial lateral overgrowth. The growth conditions were chosen to enhance the growth rate along the [0001] inclined direction. Thus, the coalescence boundaries stop the propagation of basal stacking faults. The faults filtering and the improvement of the crystalline quality were attested by transmission electron microscopy and low temperature photoluminescence. The temperature dependence of the luminescence polarization under normal incidence was also studied.

No MeSH data available.


Related in: MedlinePlus