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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.


Related in: MedlinePlus

Fracture related problems and epitaxial structures. (a) Epitaxial grating on freestanding GaN membrane, and the inset is the zoom-in view of grating region; (b), (c) and (d) the resultant 700-nm period epitaxial gratings: (b) 500-nm-wide grating; (c) 350-nm-wide grating; (d) 250-nm-wide grating.
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Figure 3: Fracture related problems and epitaxial structures. (a) Epitaxial grating on freestanding GaN membrane, and the inset is the zoom-in view of grating region; (b), (c) and (d) the resultant 700-nm period epitaxial gratings: (b) 500-nm-wide grating; (c) 350-nm-wide grating; (d) 250-nm-wide grating.

Mentions: The built-in residual stress in GaN thin film on silicon substrate, which is due to the lattice mismatch and the thermal expansion coefficient mismatch, can result in the deflection problems for freestanding GaN membrane [21]. Although thin GaN membrane can guarantee sufficient stiffness for the fabrication of freestanding gratings during DRIE of silicon process, the fracture-related problems are shown in Figure 3a are evident in the freestanding GaN membrane after the epitaxial growth of GaN. These problems might be solved by adjusting the fabrication process. In order to avoid the damage to GaN gratings, the devices are not designed in the centre of the freestanding GaN membrane. The crack networks, which are caused by the lattice mismatch in the epitaxial layers, are observed on unpatterned GaN substrate, as illustrated in the inset of Figure 3a[22]. The crack does not occur in the GaN grating region, indicating the GaN gratings can compensate the lattice mismatch.


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)

Fracture related problems and epitaxial structures. (a) Epitaxial grating on freestanding GaN membrane, and the inset is the zoom-in view of grating region; (b), (c) and (d) the resultant 700-nm period epitaxial gratings: (b) 500-nm-wide grating; (c) 350-nm-wide grating; (d) 250-nm-wide grating.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 3: Fracture related problems and epitaxial structures. (a) Epitaxial grating on freestanding GaN membrane, and the inset is the zoom-in view of grating region; (b), (c) and (d) the resultant 700-nm period epitaxial gratings: (b) 500-nm-wide grating; (c) 350-nm-wide grating; (d) 250-nm-wide grating.
Mentions: The built-in residual stress in GaN thin film on silicon substrate, which is due to the lattice mismatch and the thermal expansion coefficient mismatch, can result in the deflection problems for freestanding GaN membrane [21]. Although thin GaN membrane can guarantee sufficient stiffness for the fabrication of freestanding gratings during DRIE of silicon process, the fracture-related problems are shown in Figure 3a are evident in the freestanding GaN membrane after the epitaxial growth of GaN. These problems might be solved by adjusting the fabrication process. In order to avoid the damage to GaN gratings, the devices are not designed in the centre of the freestanding GaN membrane. The crack networks, which are caused by the lattice mismatch in the epitaxial layers, are observed on unpatterned GaN substrate, as illustrated in the inset of Figure 3a[22]. The crack does not occur in the GaN grating region, indicating the GaN gratings can compensate the lattice mismatch.

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.


Related in: MedlinePlus