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MBE Growth of AlN Nanowires on Si Substrates by Aluminizing Nucleation.

E Y, Hao Z, Yu J, Wu C, Liu R, Wang L, Xiong B, Wang J, Han Y, Sun C, Luo Y - Nanoscale Res Lett (2015)

Bottom Line: The influence of growth conditions on the morphologies of AlN NWs is carefully investigated.Island-like films are found to grow between the NWs due to poor migration ability of Al adatoms.Increasing the V/III ratio can efficiently suppress the growth of Al-polar AlN films.

View Article: PubMed Central - PubMed

Affiliation: Tsinghua National Laboratory for Information Science and Technology, Department of Electronic Engineering, Tsinghua University, Beijing, 100084, People's Republic of China. eyx11@mails.tsinghua.edu.cn.

ABSTRACT
By introducing an aluminization process to achieve nucleation of nanowires (NWs), spontaneous growth of AlN NWs on Si substrates has been realized by plasma-assisted molecular beam epitaxy. The AlN NWs are grown from the nuclei formed by the aluminization process, and the NW density and diameter can be controlled by the aluminization parameters. The influence of growth conditions on the morphologies of AlN NWs is carefully investigated. Island-like films are found to grow between the NWs due to poor migration ability of Al adatoms. The films are proved to be Al-polar different from the N-polar AlN NWs, which can explain the absence of newly formed NWs. Increasing the V/III ratio can efficiently suppress the growth of Al-polar AlN films.

No MeSH data available.


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The density and average diameter of AlN NWs versus the aluminization temperature. Solid lines are guides to the eye
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Fig3: The density and average diameter of AlN NWs versus the aluminization temperature. Solid lines are guides to the eye

Mentions: AlN NW samples B, C, and D aluminized at 850, 900, and 950 °C, respectively, were prepared to analyze the influence of the nucleation layer on the morphologies of AlN NWs. Fig. 2a is the typical SEM image of the AlN NWs, and the inset clearly shows the characteristic of a single NW. The densities and average diameters of the AlN NWs versus aluminization temperature are plotted in Fig. 3. Taking into consideration the run-to-run deviation, the densities of the AlN NWs are quite close to those of the nucleation islands of corresponding aluminization samples. It can be found that, compared to Fig. 1b, c, the sample aluminized at higher temperature has more nucleation islands with smaller average diameter, hence leading to the increase of AlN NW density and decrease of the average diameter with aluminization temperature. This implies that the AlN NWs are transformed and grown from the nucleation islands. As a contrast, sample A without aluminization process was grown under the same conditions as sample C for an elongated growth time of 3 h. However, as witnessed by the SEM image in Fig. 2b, there is an island-like film grown on the substrate instead of NWs. Therefore, it can be concluded that the aluminization process can efficiently improve the nucleation of AlN NWs.Fig. 2


MBE Growth of AlN Nanowires on Si Substrates by Aluminizing Nucleation.

E Y, Hao Z, Yu J, Wu C, Liu R, Wang L, Xiong B, Wang J, Han Y, Sun C, Luo Y - Nanoscale Res Lett (2015)

The density and average diameter of AlN NWs versus the aluminization temperature. Solid lines are guides to the eye
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4593981&req=5

Fig3: The density and average diameter of AlN NWs versus the aluminization temperature. Solid lines are guides to the eye
Mentions: AlN NW samples B, C, and D aluminized at 850, 900, and 950 °C, respectively, were prepared to analyze the influence of the nucleation layer on the morphologies of AlN NWs. Fig. 2a is the typical SEM image of the AlN NWs, and the inset clearly shows the characteristic of a single NW. The densities and average diameters of the AlN NWs versus aluminization temperature are plotted in Fig. 3. Taking into consideration the run-to-run deviation, the densities of the AlN NWs are quite close to those of the nucleation islands of corresponding aluminization samples. It can be found that, compared to Fig. 1b, c, the sample aluminized at higher temperature has more nucleation islands with smaller average diameter, hence leading to the increase of AlN NW density and decrease of the average diameter with aluminization temperature. This implies that the AlN NWs are transformed and grown from the nucleation islands. As a contrast, sample A without aluminization process was grown under the same conditions as sample C for an elongated growth time of 3 h. However, as witnessed by the SEM image in Fig. 2b, there is an island-like film grown on the substrate instead of NWs. Therefore, it can be concluded that the aluminization process can efficiently improve the nucleation of AlN NWs.Fig. 2

Bottom Line: The influence of growth conditions on the morphologies of AlN NWs is carefully investigated.Island-like films are found to grow between the NWs due to poor migration ability of Al adatoms.Increasing the V/III ratio can efficiently suppress the growth of Al-polar AlN films.

View Article: PubMed Central - PubMed

Affiliation: Tsinghua National Laboratory for Information Science and Technology, Department of Electronic Engineering, Tsinghua University, Beijing, 100084, People's Republic of China. eyx11@mails.tsinghua.edu.cn.

ABSTRACT
By introducing an aluminization process to achieve nucleation of nanowires (NWs), spontaneous growth of AlN NWs on Si substrates has been realized by plasma-assisted molecular beam epitaxy. The AlN NWs are grown from the nuclei formed by the aluminization process, and the NW density and diameter can be controlled by the aluminization parameters. The influence of growth conditions on the morphologies of AlN NWs is carefully investigated. Island-like films are found to grow between the NWs due to poor migration ability of Al adatoms. The films are proved to be Al-polar different from the N-polar AlN NWs, which can explain the absence of newly formed NWs. Increasing the V/III ratio can efficiently suppress the growth of Al-polar AlN films.

No MeSH data available.


Related in: MedlinePlus