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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.


Related in: MedlinePlus

Top-view SEM image of AlN NWs. The white circle highlights the coalescence of NWs, and the white arrow highlights the island-like film
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Fig6: Top-view SEM image of AlN NWs. The white circle highlights the coalescence of NWs, and the white arrow highlights the island-like film

Mentions: Samples J and K were grown under the same conditions as samples H and C, respectively, except for longer growth time. Figure 6 shows the typical SEM image of AlN NWs grown for 3 h. The NW density decreases while the NW length and diameter increase compared with the samples grown for 1 h. For example, the NW density, average diameter, and length of sample C are 1.1 × 109 cm−2, 33.1 nm, and 80.9 nm, while those of sample K are 7.0 × 108 cm−2, 88.2 nm, and 963.3 nm, respectively. Obviously, the axial growth rate is far higher than the radial growth rate. One possible reason for the decrease of NW density is the coalescence of NWs [15], an evidence to which is the NW highlighted by the white circle in Fig. 6. It should also be noted that, as obviously seen in Fig. 6, the AlN NWs are surrounded by island-like AlN films highlighted by the white arrows in the figure. This issue will be discussed below.Fig. 6


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)

Top-view SEM image of AlN NWs. The white circle highlights the coalescence of NWs, and the white arrow highlights the island-like film
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

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

Fig6: Top-view SEM image of AlN NWs. The white circle highlights the coalescence of NWs, and the white arrow highlights the island-like film
Mentions: Samples J and K were grown under the same conditions as samples H and C, respectively, except for longer growth time. Figure 6 shows the typical SEM image of AlN NWs grown for 3 h. The NW density decreases while the NW length and diameter increase compared with the samples grown for 1 h. For example, the NW density, average diameter, and length of sample C are 1.1 × 109 cm−2, 33.1 nm, and 80.9 nm, while those of sample K are 7.0 × 108 cm−2, 88.2 nm, and 963.3 nm, respectively. Obviously, the axial growth rate is far higher than the radial growth rate. One possible reason for the decrease of NW density is the coalescence of NWs [15], an evidence to which is the NW highlighted by the white circle in Fig. 6. It should also be noted that, as obviously seen in Fig. 6, the AlN NWs are surrounded by island-like AlN films highlighted by the white arrows in the figure. This issue will be discussed below.Fig. 6

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