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Patterned growth of InGaN/GaN quantum wells on freestanding GaN grating by molecular beam epitaxy.

Wang Y, Hu F, Hane K - Nanoscale Res Lett (2011)

Bottom Line: Importantly, coalescences between two side facets are realized to generate epitaxial gratings with triangular section.Thin epitaxial gratings produce the promising photoluminescence performance.This work provides a feasible way for further GaN-based integrated optics devices by a combination of GaN micromachining and epitaxial growth on a GaN-on-silicon substrate.PACS81.05.Ea; 81.65.Cf; 81.15.Hi.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Nanomechanics, Tohoku University, Sendai 980-8579, Japan. wyjjy@yahoo.com.

ABSTRACT
We report here the epitaxial growth of InGaN/GaN quantum wells on freestanding GaN gratings by molecular beam epitaxy (MBE). Various GaN gratings are defined by electron beam lithography and realized on GaN-on-silicon substrate by fast atom beam etching. Silicon substrate beneath GaN grating region is removed from the backside to form freestanding GaN gratings, and the patterned growth is subsequently performed on the prepared GaN template by MBE. The selective growth takes place with the assistance of nanoscale GaN gratings and depends on the grating period P and the grating width W. Importantly, coalescences between two side facets are realized to generate epitaxial gratings with triangular section. Thin epitaxial gratings produce the promising photoluminescence performance. This work provides a feasible way for further GaN-based integrated optics devices by a combination of GaN micromachining and epitaxial growth on a GaN-on-silicon substrate.PACS81.05.Ea; 81.65.Cf; 81.15.Hi.

No MeSH data available.


SEM images of the resultant epitaxial gratings. (a) 500-nm period, 200-nm-wide grating; (b) 450-nm period, 200-nm-wide grating; (c) 400-nm period, 150-nm-wide grating; (d) 400-nm period, 250-nm-wide grating.
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Figure 4: SEM images of the resultant epitaxial gratings. (a) 500-nm period, 200-nm-wide grating; (b) 450-nm period, 200-nm-wide grating; (c) 400-nm period, 150-nm-wide grating; (d) 400-nm period, 250-nm-wide grating.

Mentions: In order to be more specific, we focus our attention on the epitaxial structures grown on the grating ridge. According to the above analysis, small grating period and small grating width are helpful for improving the surface diffusion to realize the selective growth on the grating ridge. On the other hand, nanoscale grating with small grating width is difficult to fabricate. Figure 4a, b shows the epitaxial gratings on the 200-nm-wide GaN grating with the grating periods of 500 and 450 nm, respectively. Coalescences between two side facets are completed for these epitaxial gratings, and side facets are smooth with random GaN nanocolumns. The epitaxial structures on the 400-nm-period GaN gratings with the grating width W of approximately 150 nm and approximately 250 nm are illustrated in Figure 4c, d, respectively. The winding of GaN strip is found, which can be attributed the local fluctuation in the growth process. The number of epitaxial nanocolumns is increased, especially for 250-nm-wide GaN grating.


Patterned growth of InGaN/GaN quantum wells on freestanding GaN grating by molecular beam epitaxy.

Wang Y, Hu F, Hane K - Nanoscale Res Lett (2011)

SEM images of the resultant epitaxial gratings. (a) 500-nm period, 200-nm-wide grating; (b) 450-nm period, 200-nm-wide grating; (c) 400-nm period, 150-nm-wide grating; (d) 400-nm period, 250-nm-wide grating.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211162&req=5

Figure 4: SEM images of the resultant epitaxial gratings. (a) 500-nm period, 200-nm-wide grating; (b) 450-nm period, 200-nm-wide grating; (c) 400-nm period, 150-nm-wide grating; (d) 400-nm period, 250-nm-wide grating.
Mentions: In order to be more specific, we focus our attention on the epitaxial structures grown on the grating ridge. According to the above analysis, small grating period and small grating width are helpful for improving the surface diffusion to realize the selective growth on the grating ridge. On the other hand, nanoscale grating with small grating width is difficult to fabricate. Figure 4a, b shows the epitaxial gratings on the 200-nm-wide GaN grating with the grating periods of 500 and 450 nm, respectively. Coalescences between two side facets are completed for these epitaxial gratings, and side facets are smooth with random GaN nanocolumns. The epitaxial structures on the 400-nm-period GaN gratings with the grating width W of approximately 150 nm and approximately 250 nm are illustrated in Figure 4c, d, respectively. The winding of GaN strip is found, which can be attributed the local fluctuation in the growth process. The number of epitaxial nanocolumns is increased, especially for 250-nm-wide GaN grating.

Bottom Line: Importantly, coalescences between two side facets are realized to generate epitaxial gratings with triangular section.Thin epitaxial gratings produce the promising photoluminescence performance.This work provides a feasible way for further GaN-based integrated optics devices by a combination of GaN micromachining and epitaxial growth on a GaN-on-silicon substrate.PACS81.05.Ea; 81.65.Cf; 81.15.Hi.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Nanomechanics, Tohoku University, Sendai 980-8579, Japan. wyjjy@yahoo.com.

ABSTRACT
We report here the epitaxial growth of InGaN/GaN quantum wells on freestanding GaN gratings by molecular beam epitaxy (MBE). Various GaN gratings are defined by electron beam lithography and realized on GaN-on-silicon substrate by fast atom beam etching. Silicon substrate beneath GaN grating region is removed from the backside to form freestanding GaN gratings, and the patterned growth is subsequently performed on the prepared GaN template by MBE. The selective growth takes place with the assistance of nanoscale GaN gratings and depends on the grating period P and the grating width W. Importantly, coalescences between two side facets are realized to generate epitaxial gratings with triangular section. Thin epitaxial gratings produce the promising photoluminescence performance. This work provides a feasible way for further GaN-based integrated optics devices by a combination of GaN micromachining and epitaxial growth on a GaN-on-silicon substrate.PACS81.05.Ea; 81.65.Cf; 81.15.Hi.

No MeSH data available.