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Ordered GeSi nanorings grown on patterned Si (001) substrates.

Ma Y, Cui J, Fan Y, Zhong Z, Jiang Z - Nanoscale Res Lett (2011)

Bottom Line: An easy approach to fabricate ordered pattern using nanosphere lithography and reactive iron etching technology was demonstrated.The size and shape of rings were closely associated with the size of capped GeSi quantum dots and the Si capping processes.Statistical analysis on the lateral size distribution shows that the high growth temperature and the long-term annealing can improve the uniformity of nanorings.PACS code1·PACS code2·moreMathematics Subject Classification (2000) MSC code1·MSC code2·more.

View Article: PubMed Central - HTML - PubMed

Affiliation: State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, People's Republic of China. tsuijian@gmail.com.

ABSTRACT
An easy approach to fabricate ordered pattern using nanosphere lithography and reactive iron etching technology was demonstrated. Long-range ordered GeSi nanorings with 430 nm period were grown on patterned Si (001) substrates by molecular beam epitaxy. The size and shape of rings were closely associated with the size of capped GeSi quantum dots and the Si capping processes. Statistical analysis on the lateral size distribution shows that the high growth temperature and the long-term annealing can improve the uniformity of nanorings.PACS code1·PACS code2·moreMathematics Subject Classification (2000) MSC code1·MSC code2·more.

No MeSH data available.


Related in: MedlinePlus

Schematic illustration for the fabrication of ordered pit-pattern. (a) Closed-packed PS single ML pattern. (b) PS pattern after O2 RIE. (c) Au film deposition. (d) Removing PS pattern in THF. (e) KOH selective etching. (f) Inverted pyramid-like pits pattern with {111} facets after Au was removed. The panels at the right side show the AFM images at corresponding stages.
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Figure 1: Schematic illustration for the fabrication of ordered pit-pattern. (a) Closed-packed PS single ML pattern. (b) PS pattern after O2 RIE. (c) Au film deposition. (d) Removing PS pattern in THF. (e) KOH selective etching. (f) Inverted pyramid-like pits pattern with {111} facets after Au was removed. The panels at the right side show the AFM images at corresponding stages.

Mentions: The schematic illustration for nanopattern fabrication processes is shown in Figure 1. The polystyrene (PS) spheres (Duke Scientific Corporation, Palo Alto, CA, USA) used in this study have a diameter of 430 nm. The PS sphere suspension was diluted by mixing with methanol with a ratio of 1:1. First, the close-packed PS spheres monolayer (ML) was self-assembled on the surface of deionized (DI) water via Weekes' method [17]. The PS ML was then transferred onto a chemically cleaned and hydrogen-terminated surface of p-type Si (001) substrate with a resistivity of 22-32 Ω·cm by draining the DI water, as shown in Figure 1a. Second, the PS spheres ML was etched by RIE to shrink the diameter of PS spheres to about 80 nm (Figure 1b). RIE etching was done using O2 (30 sccm) at 30 W, 9.3 Pa for 10 min. Third, a 1 nm thick Au film was deposited onto the surface of the PS covered substrate (Figure 1c). Then the substrate was immersed in tetrahydrofuran (THF) under ultrasonic treatment to remove the PS spheres. A Au-Si alloy and SiO2 mask via Au-catalyzed oxidation [18] were left (Figure 1d). The substrate was then etched by KOH solution (20 wt%) at 30°C. With proper etching time, ordered inverted pyramid-like pits with {111} facets were formed, as shown in Figure 1e. The period of the pit-pattern was kept the same as that of the PS pattern, i.e., 430 nm. The average side length and the depth of the square pits was 90 and 40 nm, respectively. The Au and Au-Si alloy mask were removed by immersing the substrate in KI: I2: H2O (4:1:40) solution for 10 h [19].


Ordered GeSi nanorings grown on patterned Si (001) substrates.

Ma Y, Cui J, Fan Y, Zhong Z, Jiang Z - Nanoscale Res Lett (2011)

Schematic illustration for the fabrication of ordered pit-pattern. (a) Closed-packed PS single ML pattern. (b) PS pattern after O2 RIE. (c) Au film deposition. (d) Removing PS pattern in THF. (e) KOH selective etching. (f) Inverted pyramid-like pits pattern with {111} facets after Au was removed. The panels at the right side show the AFM images at corresponding stages.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211261&req=5

Figure 1: Schematic illustration for the fabrication of ordered pit-pattern. (a) Closed-packed PS single ML pattern. (b) PS pattern after O2 RIE. (c) Au film deposition. (d) Removing PS pattern in THF. (e) KOH selective etching. (f) Inverted pyramid-like pits pattern with {111} facets after Au was removed. The panels at the right side show the AFM images at corresponding stages.
Mentions: The schematic illustration for nanopattern fabrication processes is shown in Figure 1. The polystyrene (PS) spheres (Duke Scientific Corporation, Palo Alto, CA, USA) used in this study have a diameter of 430 nm. The PS sphere suspension was diluted by mixing with methanol with a ratio of 1:1. First, the close-packed PS spheres monolayer (ML) was self-assembled on the surface of deionized (DI) water via Weekes' method [17]. The PS ML was then transferred onto a chemically cleaned and hydrogen-terminated surface of p-type Si (001) substrate with a resistivity of 22-32 Ω·cm by draining the DI water, as shown in Figure 1a. Second, the PS spheres ML was etched by RIE to shrink the diameter of PS spheres to about 80 nm (Figure 1b). RIE etching was done using O2 (30 sccm) at 30 W, 9.3 Pa for 10 min. Third, a 1 nm thick Au film was deposited onto the surface of the PS covered substrate (Figure 1c). Then the substrate was immersed in tetrahydrofuran (THF) under ultrasonic treatment to remove the PS spheres. A Au-Si alloy and SiO2 mask via Au-catalyzed oxidation [18] were left (Figure 1d). The substrate was then etched by KOH solution (20 wt%) at 30°C. With proper etching time, ordered inverted pyramid-like pits with {111} facets were formed, as shown in Figure 1e. The period of the pit-pattern was kept the same as that of the PS pattern, i.e., 430 nm. The average side length and the depth of the square pits was 90 and 40 nm, respectively. The Au and Au-Si alloy mask were removed by immersing the substrate in KI: I2: H2O (4:1:40) solution for 10 h [19].

Bottom Line: An easy approach to fabricate ordered pattern using nanosphere lithography and reactive iron etching technology was demonstrated.The size and shape of rings were closely associated with the size of capped GeSi quantum dots and the Si capping processes.Statistical analysis on the lateral size distribution shows that the high growth temperature and the long-term annealing can improve the uniformity of nanorings.PACS code1·PACS code2·moreMathematics Subject Classification (2000) MSC code1·MSC code2·more.

View Article: PubMed Central - HTML - PubMed

Affiliation: State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, People's Republic of China. tsuijian@gmail.com.

ABSTRACT
An easy approach to fabricate ordered pattern using nanosphere lithography and reactive iron etching technology was demonstrated. Long-range ordered GeSi nanorings with 430 nm period were grown on patterned Si (001) substrates by molecular beam epitaxy. The size and shape of rings were closely associated with the size of capped GeSi quantum dots and the Si capping processes. Statistical analysis on the lateral size distribution shows that the high growth temperature and the long-term annealing can improve the uniformity of nanorings.PACS code1·PACS code2·moreMathematics Subject Classification (2000) MSC code1·MSC code2·more.

No MeSH data available.


Related in: MedlinePlus